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Paul E. McKenney [Wed, 5 Apr 2017 16:01:53 +0000 (09:01 -0700)]
srcu: Parallelize callback handling
Peter Zijlstra proposed using SRCU to reduce mmap_sem contention [1,2],
however, there are workloads that could result in a high volume of
concurrent invocations of call_srcu(), which with current SRCU would
result in excessive lock contention on the srcu_struct structure's
->queue_lock, which protects SRCU's callback lists. This commit therefore
moves SRCU to per-CPU callback lists, thus greatly reducing contention.
Because a given SRCU instance no longer has a single centralized callback
list, starting grace periods and invoking callbacks are both more complex
than in the single-list Classic SRCU implementation. Starting grace
periods and handling callbacks are now handled using an srcu_node tree
that is in some ways similar to the rcu_node trees used by RCU-bh,
RCU-preempt, and RCU-sched (for example, the srcu_node tree shape is
controlled by exactly the same Kconfig options and boot parameters that
control the shape of the rcu_node tree).
In addition, the old per-CPU srcu_array structure is now named srcu_data
and contains an rcu_segcblist structure named ->srcu_cblist for its
callbacks (and a spinlock to protect this). The srcu_struct gets
an srcu_gp_seq that is used to associate callback segments with the
corresponding completion-time grace-period number. These completion-time
grace-period numbers are propagated up the srcu_node tree so that the
grace-period workqueue handler can determine whether additional grace
periods are needed on the one hand and where to look for callbacks that
are ready to be invoked.
The srcu_barrier() function must now wait on all instances of the per-CPU
->srcu_cblist. Because each ->srcu_cblist is protected by ->lock,
srcu_barrier() can remotely add the needed callbacks. In theory,
it could also remotely start grace periods, but in practice doing so
is complex and racy. And interestingly enough, it is never necessary
for srcu_barrier() to start a grace period because srcu_barrier() only
enqueues a callback when a callback is already present--and it turns out
that a grace period has to have already been started for this pre-existing
callback. Furthermore, it is only the callback that srcu_barrier()
needs to wait on, not any particular grace period. Therefore, a new
rcu_segcblist_entrain() function enqueues the srcu_barrier() function's
callback into the same segment occupied by the last pre-existing callback
in the list. The special case where all the pre-existing callbacks are
on a different list (because they are in the process of being invoked)
is handled by enqueuing srcu_barrier()'s callback into the RCU_DONE_TAIL
segment, relying on the done-callbacks check that takes place after all
callbacks are inovked.
Note that the readers use the same algorithm as before. Note that there
is a separate srcu_idx that tells the readers what counter to increment.
This unfortunately cannot be combined with srcu_gp_seq because they
need to be incremented at different times.
This commit introduces some ugly #ifdefs in rcutorture. These will go
away when I feel good enough about Tree SRCU to ditch Classic SRCU.
Some crude performance comparisons, courtesy of a quickly hacked rcuperf
asynchronous-grace-period capability:
Callback Queuing Overhead
-------------------------
# CPUS Classic SRCU Tree SRCU
------ ------------ ---------
2 0.349 us 0.342 us
16 31.66 us 0.4 us
41 --------- 0.417 us
The times are the 90th percentiles, a statistic that was chosen to reject
the overheads of the occasional srcu_barrier() call needed to avoid OOMing
the test machine. The rcuperf test hangs when running Classic SRCU at 41
CPUs, hence the line of dashes. Despite the hacks to both the rcuperf code
and that statistics, this is a convincing demonstration of Tree SRCU's
performance and scalability advantages.
[1] https://lwn.net/Articles/309030/
[2] https://patchwork.kernel.org/patch/
5108281/
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Fix initialization if synchronize_srcu_expedited() called first. ]
Paul E. McKenney [Fri, 21 Apr 2017 00:30:06 +0000 (17:30 -0700)]
kvm: Move srcu_struct fields to end of struct kvm
Parallelizing SRCU callback handling will increase the size of
srcu_struct, which will move the kvm structure's kvm_arch field out
of reach of powerpc's current assembly code, which will result in the
following sort of build error:
arch/powerpc/kvm/book3s_hv_rmhandlers.S:617: Error: operand out of range (0x000000000000b328 is not between 0xffffffffffff8000 and 0x0000000000007fff)
This commit moves the srcu_struct fields in the kvm structure to follow
the kvm_arch field, which will allow powerpc's assembly code to continue
to be able to reach the kvm_arch field.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Michael Ellerman <michaele@au1.ibm.com>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
[ paulmck: Moved this commit to precede SRCU callback parallelization,
and reworded the commit log into future tense, all in the name of
bisectability. ]
Paul E. McKenney [Sun, 26 Mar 2017 00:23:44 +0000 (17:23 -0700)]
srcu: Introduce CLASSIC_SRCU Kconfig option
The TREE_SRCU rewrite is large and a bit on the non-simple side, so
this commit helps reduce risk by allowing the old v4.11 SRCU algorithm
to be selected using a new CLASSIC_SRCU Kconfig option that depends
on RCU_EXPERT. The default is to use the new TREE_SRCU and TINY_SRCU
algorithms, in order to help get these the testing that they need.
However, if your users do not require the update-side scalability that
is to be provided by TREE_SRCU, select RCU_EXPERT and then CLASSIC_SRCU
to revert back to the old classic SRCU algorithm.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Sat, 25 Mar 2017 18:34:42 +0000 (11:34 -0700)]
srcutorture: Print Tiny SRCU reader statistics
The srcu_torture_stats() function is adapted to the specific srcu_struct
layout traditionally used by SRCU. This commit therefore adds support
for Tiny SRCU.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Sat, 25 Mar 2017 16:59:38 +0000 (09:59 -0700)]
srcu: Create a tiny SRCU
In response to automated complaints about modifications to SRCU
increasing its size, this commit creates a tiny SRCU that is
used in SMP=n && PREEMPT=n builds.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Sat, 25 Mar 2017 17:42:07 +0000 (10:42 -0700)]
mm: Use static initialization for "srcu"
The MM-notifier code currently dynamically initializes the srcu_struct
named "srcu" at subsys_initcall() time, and includes a BUG_ON() to check
this initialization in do_mmu_notifier_register(). Unfortunately, there
is no foolproof way to verify that an srcu_struct has been initialized,
given the possibility of an srcu_struct being allocated on the stack or
on the heap. This means that creating an srcu_struct_is_initialized()
function is not a reasonable course of action. Nor is peppering
do_mmu_notifier_register() with SRCU-specific #ifdefs an attractive
alternative.
This commit therefore uses DEFINE_STATIC_SRCU() to initialize
this srcu_struct at compile time, thus eliminating both the
subsys_initcall()-time initialization and the runtime BUG_ON().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <linux-mm@kvack.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Paul E. McKenney [Fri, 24 Mar 2017 20:46:33 +0000 (13:46 -0700)]
srcu: Crude control of expedited grace periods
SRCU's implementation of expedited grace periods has always assumed
that the SRCU instance is idle when the expedited request arrives.
This commit improves this a bit by maintaining a count of the number
of outstanding expedited requests, thus allowing prior non-expedited
grace periods accommodate these requests by shifting to expedited mode.
However, any non-expedited wait already in progress will still wait for
the full duration.
Improved control of expedited grace periods is planned, but one step
at a time.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Wed, 22 Mar 2017 22:26:18 +0000 (15:26 -0700)]
srcu: Merge ->srcu_state into ->srcu_gp_seq
Updating ->srcu_state and ->srcu_gp_seq will lead to extremely complex
race conditions given multiple callback queues, so this commit takes
advantage of the two-bit state now available in rcu_seq counters to
store the state in the bottom two bits of ->srcu_gp_seq.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Tue, 21 Mar 2017 17:35:57 +0000 (10:35 -0700)]
srcu: Allow a second bit in rcu_seq for SRCU state
This commit increases the number of reserved bits at the bottom of an
rcu_seq grace-period counter from one to two, as will be needed to
accommodate SRCU's three-state grace periods.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Tue, 21 Mar 2017 14:28:14 +0000 (07:28 -0700)]
srcu: Improve rcu_seq grace-period-counter abstraction
The expedited grace-period code contains several open-coded shifts
know the format of an rcu_seq grace-period counter, which is not
particularly good style. This commit therefore creates a new
rcu_seq_ctr() function that extracts the counter portion of the
counter, and an rcu_seq_state() function that extracts the low-order
state bit. This commit prepares for SRCU callback parallelization,
which will require two state bits.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Wed, 15 Mar 2017 23:34:11 +0000 (16:34 -0700)]
srcu: Fix bogus try_check_zero() comment
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Wed, 15 Mar 2017 20:11:11 +0000 (13:11 -0700)]
srcu: Make num_rcu_lvl[] array be external
This commit makes the num_rcu_lvl[] array external so that SRCU can
make use of it for initializing its upcoming srcu_node tree.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Wed, 15 Mar 2017 20:07:53 +0000 (13:07 -0700)]
srcu: Move rcu_node traversal macros to rcu.h
This commit moves rcu_for_each_node_breadth_first(),
rcu_for_each_nonleaf_node_breadth_first(), and
rcu_for_each_leaf_node() from kernel/rcu/tree.h to
kernel/rcu/rcu.h so that SRCU can access them.
This commit is code-movement only.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Wed, 15 Mar 2017 19:59:17 +0000 (12:59 -0700)]
rcu: Remove redundant levelcnt[] array from rcu_init_one()
The levelcnt[] array is identical to num_rcu_lvl[], so this commit
removes levelcnt[].
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Tue, 14 Mar 2017 21:29:53 +0000 (14:29 -0700)]
srcu: Move rcu_init_levelspread() to rcu_tree_node.h
This commit moves the rcu_init_levelspread() function from
kernel/rcu/tree.c to kernel/rcu/rcu.h so that SRCU can access it. This is
another step towards enabling SRCU to create its own combining tree.
This commit is code-movement only, give or take knock-on adjustments.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Tue, 14 Mar 2017 19:42:30 +0000 (12:42 -0700)]
srcu: Move combining-tree definitions for SRCU's benefit
This commit moves the C preprocessor code that defines the default shape
of the rcu_node combining tree to a new include/linux/rcu_node_tree.h
file as a first step towards enabling SRCU to create its own combining
tree, which in turn enables SRCU to implement per-CPU callback handling,
thus avoiding contention on the lock currently guarding the single list
of callbacks. Note that users of SRCU still need to know the size of
the srcu_struct structure, hence include/linux rather than kernel/rcu.
This commit is code-movement only.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Mon, 13 Mar 2017 23:48:18 +0000 (16:48 -0700)]
srcu: Use rcu_segcblist to track SRCU callbacks
This commit switches SRCU from custom-built callback queues to the new
rcu_segcblist structure. This change associates grace-period sequence
numbers with groups of callbacks, which will be needed for efficient
processing of per-CPU callbacks.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Sat, 11 Mar 2017 15:14:06 +0000 (07:14 -0800)]
srcu: Add grace-period sequence numbers
This commit adds grace-period sequence numbers, which will be used to
handle mid-boot grace periods and per-CPU callback lists.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Fri, 10 Mar 2017 23:31:55 +0000 (15:31 -0800)]
srcu: Move to state-based grace-period sequencing
The current SRCU grace-period processing might never reach the last
portion of srcu_advance_batches(). This is OK given the current
implementation, as the first portion, up to the try_check_zero()
following the srcu_flip() is sufficient to drive grace periods forward.
However, it has the unfortunate side-effect of making it impossible to
determine when a given grace period has ended, and it will be necessary
to efficiently trace ends of grace periods in order to efficiently handle
per-CPU SRCU callback lists.
This commit therefore adds states to the SRCU grace-period processing,
so that the end of a given SRCU grace period is marked by the transition
to the SRCU_STATE_DONE state.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Fri, 10 Mar 2017 00:16:42 +0000 (16:16 -0800)]
srcu: Push srcu_advance_batches() fastpath into common case
This commit simplifies the SRCU state machine by pushing the
srcu_advance_batches() idle-SRCU fastpath into the common case. This is
done by giving srcu_reschedule() a delay parameter, which is zero in
the call from srcu_advance_batches().
This commit is a step towards numbering callbacks in order to
efficiently handle per-CPU callback lists.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Dmitry Vyukov [Sun, 5 Mar 2017 20:17:31 +0000 (12:17 -0800)]
rcu: Fix warning in rcu_seq_end()
The rcu_seq_end() function increments seq signifying completion
of a grace period, after that checks that the seq is even and wakes
_synchronize_rcu_expedited(). The _synchronize_rcu_expedited() function
uses wait_event() to wait for even seq. The problem is that wait_event()
can return as soon as seq becomes even without waiting for the wakeup.
In such case the warning in rcu_seq_end() can falsely fire if the next
expedited grace period starts before the check.
Check that seq has good value before incrementing it.
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: syzkaller@googlegroups.com
Cc: linux-kernel@vger.kernel.org
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: josh@joshtriplett.org
Cc: jiangshanlai@gmail.com
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
syzkaller-triggered warning:
WARNING: CPU: 0 PID: 4832 at kernel/rcu/tree.c:3533
rcu_seq_end+0x110/0x140 kernel/rcu/tree.c:3533
CPU: 0 PID: 4832 Comm: kworker/0:3 Not tainted 4.10.0+ #276
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Workqueue: events wait_rcu_exp_gp
Call Trace:
__dump_stack lib/dump_stack.c:15 [inline]
dump_stack+0x2ee/0x3ef lib/dump_stack.c:51
panic+0x1fb/0x412 kernel/panic.c:179
__warn+0x1c4/0x1e0 kernel/panic.c:540
warn_slowpath_null+0x2c/0x40 kernel/panic.c:583
rcu_seq_end+0x110/0x140 kernel/rcu/tree.c:3533
rcu_exp_gp_seq_end kernel/rcu/tree_exp.h:36 [inline]
rcu_exp_wait_wake+0x8a9/0x1330 kernel/rcu/tree_exp.h:517
rcu_exp_sel_wait_wake kernel/rcu/tree_exp.h:559 [inline]
wait_rcu_exp_gp+0x83/0xc0 kernel/rcu/tree_exp.h:570
process_one_work+0xc06/0x1c20 kernel/workqueue.c:2096
worker_thread+0x223/0x19c0 kernel/workqueue.c:2230
kthread+0x326/0x3f0 kernel/kthread.c:227
ret_from_fork+0x31/0x40 arch/x86/entry/entry_64.S:430
---
Paul E. McKenney [Sat, 4 Mar 2017 20:33:53 +0000 (12:33 -0800)]
rcu: Expedited wakeups need to be fully ordered
Expedited grace periods use workqueue handlers that wake up the requesters,
but there is no lock mediating this wakeup. Therefore, memory barriers
are required to ensure that the handler's memory references are seen by
all to occur before synchronize_*_expedited() returns to its caller.
Possibly detected by syzkaller.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Mon, 20 Feb 2017 22:57:17 +0000 (14:57 -0800)]
srcu: Move rcu_seq_start() and friends to rcu.h
This commit moves rcu_seq_start(), rcu_seq_end(), rcu_seq_snap(),
and rcu_seq_done() from kernel/rcu/tree.c to kernel/rcu/rcu.h.
This will allow SRCU to use these functions, which in turn will
allow SRCU to move from a single global callback queue to a
per-CPU callback queue.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Thu, 16 Feb 2017 01:50:50 +0000 (17:50 -0800)]
rcu: Add single-element dequeue functions to rcu_segcblist
This commit adds single-element dequeue functions to rcu_segcblist.
These are less efficient than using the extract and insert functions,
but allow more precise debugging code. These functions are thus
expected to be used only in debug builds, for example, CONFIG_PROVE_RCU.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Fri, 10 Feb 2017 22:50:46 +0000 (14:50 -0800)]
srcu: Allow early boot use of synchronize_srcu()
This commit checks for pre-scheduler state, and if that early in the
boot process, synchronize_srcu() and friends are no-ops.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Fri, 10 Feb 2017 22:32:54 +0000 (14:32 -0800)]
srcu: Allow SRCU to access rcu_scheduler_active
This is primarily a code-movement commit in preparation for allowing
SRCU to handle early-boot SRCU grace periods.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Wed, 8 Feb 2017 20:36:42 +0000 (12:36 -0800)]
srcu: Abstract multi-tail callback list handling
RCU has only one multi-tail callback list, which is implemented via
the nxtlist, nxttail, nxtcompleted, qlen_lazy, and qlen fields in the
rcu_data structure, and whose operations are open-code throughout the
Tree RCU implementation. This has been more or less OK in the past,
but upcoming callback-list optimizations in SRCU could really use
a multi-tail callback list there as well.
This commit therefore abstracts the multi-tail callback list handling
into a new kernel/rcu/rcu_segcblist.h file, and uses this new API.
The simple head-and-tail pointer callback list is also abstracted and
applied everywhere except for the NOCB callback-offload lists. (Yes,
the plan is to apply them there as well, but this commit is already
bigger than would be good.)
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Fri, 3 Feb 2017 17:54:05 +0000 (09:54 -0800)]
rcu: Default RCU_FANOUT_LEAF to 16 unless explicitly changed
If the RCU_EXPERT Kconfig option is not set (the default), then the
RCU_FANOUT_LEAF Kconfig option will not be defined, which will cause
the leaf-level rcu_node tree fanout to default to 32 on 32-bit systems
and 64 on 64-bit systems. This can result in excessive lock contention.
This commit therefore changes the computation of the leaf-level rcu_node
tree fanout so that the result will be 16 unless an explicit Kconfig or
kernel-boot setting says otherwise.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Fri, 27 Jan 2017 22:17:50 +0000 (14:17 -0800)]
rcu: Place guard on rcu_all_qs() and rcu_note_context_switch() actions
The rcu_all_qs() and rcu_note_context_switch() do a series of checks,
taking various actions to supply RCU with quiescent states, depending
on the outcomes of the various checks. This is a bit much for scheduling
fastpaths, so this commit creates a separate ->rcu_urgent_qs field in
the rcu_dynticks structure that acts as a global guard for these checks.
Thus, in the common case, rcu_all_qs() and rcu_note_context_switch()
check the ->rcu_urgent_qs field, find it false, and simply return.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Paul E. McKenney [Fri, 27 Jan 2017 21:17:02 +0000 (13:17 -0800)]
rcu: Eliminate flavor scan in rcu_momentary_dyntick_idle()
The rcu_momentary_dyntick_idle() function scans the RCU flavors, checking
that one of them still needs a quiescent state before doing an expensive
atomic operation on the ->dynticks counter. However, this check reduces
overhead only after a rare race condition, and increases complexity. This
commit therefore removes the scan and the mechanism enabling the scan.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Fri, 27 Jan 2017 00:18:07 +0000 (16:18 -0800)]
rcu: Pull rcu_qs_ctr into rcu_dynticks structure
The rcu_qs_ctr variable is yet another isolated per-CPU variable,
so this commit pulls it into the pre-existing rcu_dynticks per-CPU
structure.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Thu, 26 Jan 2017 21:45:38 +0000 (13:45 -0800)]
rcu: Pull rcu_sched_qs_mask into rcu_dynticks structure
The rcu_sched_qs_mask variable is yet another isolated per-CPU variable,
so this commit pulls it into the pre-existing rcu_dynticks per-CPU
structure.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Mon, 23 Jan 2017 20:04:46 +0000 (12:04 -0800)]
rcu: Semicolon inside RCU_TRACE() for tree.c
The current use of "RCU_TRACE(statement);" can cause odd bugs, especially
where "statement" is a local-variable declaration, as it can leave a
misplaced ";" in the source code. This commit therefore converts these
to "RCU_TRACE(statement;)", which avoids the misplaced ";".
Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Mon, 23 Jan 2017 20:02:09 +0000 (12:02 -0800)]
rcu: Semicolon inside RCU_TRACE() for Tiny RCU
The current use of "RCU_TRACE(statement);" can cause odd bugs, especially
where "statement" is a local-variable declaration, as it can leave a
misplaced ";" in the source code. This commit therefore converts these
to "RCU_TRACE(statement;)", which avoids the misplaced ";".
Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Mon, 23 Jan 2017 19:55:43 +0000 (11:55 -0800)]
rcu: Semicolon inside RCU_TRACE() for rcu.h
The current use of "RCU_TRACE(statement);" can cause odd bugs, especially
where "statement" is a local-variable declaration, as it can leave a
misplaced ";" in the source code. This commit therefore converts these
to "RCU_TRACE(statement;)", which avoids the misplaced ";".
Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Thu, 19 Jan 2017 21:40:09 +0000 (13:40 -0800)]
srcu: Check for tardy grace-period activity in cleanup_srcu_struct()
Users of SRCU are obliged to complete all grace-period activity before
invoking cleanup_srcu_struct(). This means that all calls to either
synchronize_srcu() or synchronize_srcu_expedited() must have returned,
and all calls to call_srcu() must have returned, and the last call to
call_srcu() must have been followed by a call to srcu_barrier().
Furthermore, the caller must have done something to prevent any
further calls to synchronize_srcu(), synchronize_srcu_expedited(),
and call_srcu().
Therefore, if there has ever been an invocation of call_srcu() on
the srcu_struct in question, the sequence of events must be as
follows:
1. Prevent any further calls to call_srcu().
2. Wait for any pre-existing call_srcu() invocations to return.
3. Invoke srcu_barrier().
4. It is now safe to invoke cleanup_srcu_struct().
On the other hand, if there has ever been a call to synchronize_srcu()
or synchronize_srcu_expedited(), the sequence of events must be as
follows:
1. Prevent any further calls to synchronize_srcu() or
synchronize_srcu_expedited().
2. Wait for any pre-existing synchronize_srcu() or
synchronize_srcu_expedited() invocations to return.
3. It is now safe to invoke cleanup_srcu_struct().
If there have been calls to all both types of functions (call_srcu()
and either of synchronize_srcu() and synchronize_srcu_expedited()), then
the caller must do the first three steps of the call_srcu() procedure
above and the first two steps of the synchronize_s*() procedure above,
and only then invoke cleanup_srcu_struct().
Note that cleanup_srcu_struct() does some probabilistic checks
for the caller failing to follow these procedures, in which case
cleanup_srcu_struct() does WARN_ON() and avoids freeing the per-CPU
structures associated with the specified srcu_struct structure.
Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Thu, 19 Jan 2017 21:33:17 +0000 (13:33 -0800)]
srcu: Consolidate batch checking into rcu_all_batches_empty()
The srcu_reschedule() function invokes rcu_batch_empty() on each of
the four rcu_batch structures in the srcu_struct in question twice.
Given that this check will also be needed in cleanup_srcu_struct(), this
commit consolidates these four checks into a new rcu_all_batches_empty()
function.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Sat, 14 Jan 2017 21:32:50 +0000 (13:32 -0800)]
rcu: Make arch select smp_mb__after_unlock_lock() strength
The definition of smp_mb__after_unlock_lock() is currently smp_mb()
for CONFIG_PPC and a no-op otherwise. It would be better to instead
provide an architecture-selectable Kconfig option, and select the
strength of smp_mb__after_unlock_lock() based on that option. This
commit therefore creates ARCH_WEAK_RELEASE_ACQUIRE, has PPC select it,
and bases the definition of smp_mb__after_unlock_lock() on this new
ARCH_WEAK_RELEASE_ACQUIRE Kconfig option.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Boqun Feng <boqun.feng@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: <linuxppc-dev@lists.ozlabs.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Tue, 8 Nov 2016 22:25:21 +0000 (14:25 -0800)]
rcu: Maintain special bits at bottom of ->dynticks counter
Currently, IPIs are used to force other CPUs to invalidate their TLBs
in response to a kernel virtual-memory mapping change. This works, but
degrades both battery lifetime (for idle CPUs) and real-time response
(for nohz_full CPUs), and in addition results in unnecessary IPIs due to
the fact that CPUs executing in usermode are unaffected by stale kernel
mappings. It would be better to cause a CPU executing in usermode to
wait until it is entering kernel mode to do the flush, first to avoid
interrupting usemode tasks and second to handle multiple flush requests
with a single flush in the case of a long-running user task.
This commit therefore reserves a bit at the bottom of the ->dynticks
counter, which is checked upon exit from extended quiescent states.
If it is set, it is cleared and then a new rcu_eqs_special_exit() macro is
invoked, which, if not supplied, is an empty single-pass do-while loop.
If this bottom bit is set on -entry- to an extended quiescent state,
then a WARN_ON_ONCE() triggers.
This bottom bit may be set using a new rcu_eqs_special_set() function,
which returns true if the bit was set, or false if the CPU turned
out to not be in an extended quiescent state. Please note that this
function refuses to set the bit for a non-nohz_full CPU when that CPU
is executing in usermode because usermode execution is tracked by RCU
as a dyntick-idle extended quiescent state only for nohz_full CPUs.
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Linus Torvalds [Sun, 12 Mar 2017 21:47:08 +0000 (14:47 -0700)]
Linux 4.11-rc2
Linus Torvalds [Sun, 12 Mar 2017 21:22:25 +0000 (14:22 -0700)]
Merge branch 'for-linus' of git://git./linux/kernel/git/s390/linux
Pull s390 fixes from Martin Schwidefsky:
- four patches to get the new cputime code in shape for s390
- add the new statx system call
- a few bug fixes
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390: wire up statx system call
KVM: s390: Fix guest migration for huge guests resulting in panic
s390/ipl: always use load normal for CCW-type re-IPL
s390/timex: micro optimization for tod_to_ns
s390/cputime: provide archicture specific cputime_to_nsecs
s390/cputime: reset all accounting fields on fork
s390/cputime: remove last traces of cputime_t
s390: fix in-kernel program checks
s390/crypt: fix missing unlock in ctr_paes_crypt on error path
Linus Torvalds [Sun, 12 Mar 2017 21:18:49 +0000 (14:18 -0700)]
Merge branch 'x86-urgent-for-linus' of git://git./linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner:
- a fix for the kexec/purgatory regression which was introduced in the
merge window via an innocent sparse fix. We could have reverted that
commit, but on deeper inspection it turned out that the whole
machinery is neither documented nor robust. So a proper cleanup was
done instead
- the fix for the TLB flush issue which was discovered recently
- a simple typo fix for a reboot quirk
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/tlb: Fix tlb flushing when lguest clears PGE
kexec, x86/purgatory: Unbreak it and clean it up
x86/reboot/quirks: Fix typo in ASUS EeeBook X205TA reboot quirk
Linus Torvalds [Sun, 12 Mar 2017 21:11:38 +0000 (14:11 -0700)]
Merge branch 'irq-urgent-for-linus' of git://git./linux/kernel/git/tip/tip
Pull irq fixes from Thomas Gleixner:
- a workaround for a GIC erratum
- a missing stub function for CONFIG_IRQDOMAIN=n
- fixes for a couple of type inconsistencies
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/crossbar: Fix incorrect type of register size
irqchip/gicv3-its: Add workaround for QDF2400 ITS erratum 0065
irqdomain: Add empty irq_domain_check_msi_remap
irqchip/crossbar: Fix incorrect type of local variables
Daniel Borkmann [Sat, 11 Mar 2017 00:31:19 +0000 (01:31 +0100)]
x86/tlb: Fix tlb flushing when lguest clears PGE
Fengguang reported random corruptions from various locations on x86-32
after commits
d2852a224050 ("arch: add ARCH_HAS_SET_MEMORY config") and
9d876e79df6a ("bpf: fix unlocking of jited image when module ronx not set")
that uses the former. While x86-32 doesn't have a JIT like x86_64, the
bpf_prog_lock_ro() and bpf_prog_unlock_ro() got enabled due to
ARCH_HAS_SET_MEMORY, whereas Fengguang's test kernel doesn't have module
support built in and therefore never had the DEBUG_SET_MODULE_RONX setting
enabled.
After investigating the crashes further, it turned out that using
set_memory_ro() and set_memory_rw() didn't have the desired effect, for
example, setting the pages as read-only on x86-32 would still let
probe_kernel_write() succeed without error. This behavior would manifest
itself in situations where the vmalloc'ed buffer was accessed prior to
set_memory_*() such as in case of bpf_prog_alloc(). In cases where it
wasn't, the page attribute changes seemed to have taken effect, leading to
the conclusion that a TLB invalidate didn't happen. Moreover, it turned out
that this issue reproduced with qemu in "-cpu kvm64" mode, but not for
"-cpu host". When the issue occurs, change_page_attr_set_clr() did trigger
a TLB flush as expected via __flush_tlb_all() through cpa_flush_range(),
though.
There are 3 variants for issuing a TLB flush: invpcid_flush_all() (depends
on CPU feature bits X86_FEATURE_INVPCID, X86_FEATURE_PGE), cr4 based flush
(depends on X86_FEATURE_PGE), and cr3 based flush. For "-cpu host" case in
my setup, the flush used invpcid_flush_all() variant, whereas for "-cpu
kvm64", the flush was cr4 based. Switching the kvm64 case to cr3 manually
worked fine, and further investigating the cr4 one turned out that
X86_CR4_PGE bit was not set in cr4 register, meaning the
__native_flush_tlb_global_irq_disabled() wrote cr4 twice with the same
value instead of clearing X86_CR4_PGE in the first write to trigger the
flush.
It turned out that X86_CR4_PGE was cleared from cr4 during init from
lguest_arch_host_init() via adjust_pge(). The X86_FEATURE_PGE bit is also
cleared from there due to concerns of using PGE in guest kernel that can
lead to hard to trace bugs (see
bff672e630a0 ("lguest: documentation V:
Host") in init()). The CPU feature bits are cleared in dynamic
boot_cpu_data, but they never propagated to __flush_tlb_all() as it uses
static_cpu_has() instead of boot_cpu_has() for testing which variant of TLB
flushing to use, meaning they still used the old setting of the host
kernel.
Clearing via setup_clear_cpu_cap(X86_FEATURE_PGE) so this would propagate
to static_cpu_has() checks is too late at this point as sections have been
patched already, so for now, it seems reasonable to switch back to
boot_cpu_has(X86_FEATURE_PGE) as it was prior to commit
c109bf95992b
("x86/cpufeature: Remove cpu_has_pge"). This lets the TLB flush trigger via
cr3 as originally intended, properly makes the new page attributes visible
and thus fixes the crashes seen by Fengguang.
Fixes:
c109bf95992b ("x86/cpufeature: Remove cpu_has_pge")
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: bp@suse.de
Cc: Kees Cook <keescook@chromium.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: lkp@01.org
Cc: Laura Abbott <labbott@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernrl.org/r/20170301125426.l4nf65rx4wahohyl@wfg-t540p.sh.intel.com
Link: http://lkml.kernel.org/r/25c41ad9eca164be4db9ad84f768965b7eb19d9e.1489191673.git.daniel@iogearbox.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Linus Torvalds [Sat, 11 Mar 2017 22:24:58 +0000 (14:24 -0800)]
Merge tag 'for-linus' of git://git./virt/kvm/kvm
Pull KVM fixes from Radim Krčmář:
"ARM updates from Marc Zyngier:
- vgic updates:
- Honour disabling the ITS
- Don't deadlock when deactivating own interrupts via MMIO
- Correctly expose the lact of IRQ/FIQ bypass on GICv3
- I/O virtualization:
- Make KVM_CAP_NR_MEMSLOTS big enough for large guests with many
PCIe devices
- General bug fixes:
- Gracefully handle exception generated with syndroms that the host
doesn't understand
- Properly invalidate TLBs on VHE systems
x86:
- improvements in emulation of VMCLEAR, VMX MSR bitmaps, and VCPU
reset
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: nVMX: do not warn when MSR bitmap address is not backed
KVM: arm64: Increase number of user memslots to 512
KVM: arm/arm64: Remove KVM_PRIVATE_MEM_SLOTS definition that are unused
KVM: arm/arm64: Enable KVM_CAP_NR_MEMSLOTS on arm/arm64
KVM: Add documentation for KVM_CAP_NR_MEMSLOTS
KVM: arm/arm64: VGIC: Fix command handling while ITS being disabled
arm64: KVM: Survive unknown traps from guests
arm: KVM: Survive unknown traps from guests
KVM: arm/arm64: Let vcpu thread modify its own active state
KVM: nVMX: reset nested_run_pending if the vCPU is going to be reset
kvm: nVMX: VMCLEAR should not cause the vCPU to shut down
KVM: arm/arm64: vgic-v3: Don't pretend to support IRQ/FIQ bypass
arm64: KVM: VHE: Clear HCR_TGE when invalidating guest TLBs
Linus Torvalds [Sat, 11 Mar 2017 22:16:50 +0000 (14:16 -0800)]
Merge tag 'extable-fix' of git://git./linux/kernel/git/paulg/linux
Pull extable.h fix from Paul Gortmaker:
"Fixup for arch/score after extable.h introduction.
It seems that Guenter is the only one on the planet doing builds for
arch/score -- we don't have compile coverage for it in linux-next or
in the kbuild-bot either. Guenter couldn't even recall where he got
his toolchain, but was kind enough to share it with me so I could
validate this change and also add arch/score to my build coverage.
I sat on this a bit in case there was any other fallout in other arch
dirs, but since this still seems to be the only one, I might as well
send it on its way"
* tag 'extable-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
score: Fix implicit includes now failing build after extable change
Linus Torvalds [Sat, 11 Mar 2017 17:08:47 +0000 (09:08 -0800)]
Merge tag 'random_for_linus' of git://git./linux/kernel/git/tytso/random
Pull random updates from Ted Ts'o:
"Change get_random_{int,log} to use the CRNG used by /dev/urandom and
getrandom(2). It's faster and arguably more secure than cut-down MD5
that we had been using.
Also do some code cleanup"
* tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
random: move random_min_urandom_seed into CONFIG_SYSCTL ifdef block
random: convert get_random_int/long into get_random_u32/u64
random: use chacha20 for get_random_int/long
random: fix comment for unused random_min_urandom_seed
random: remove variable limit
random: remove stale urandom_init_wait
random: remove stale maybe_reseed_primary_crng
Guenter Roeck [Wed, 22 Feb 2017 19:07:57 +0000 (11:07 -0800)]
score: Fix implicit includes now failing build after extable change
After changing from module.h to extable.h, score builds fail with:
arch/score/kernel/traps.c: In function 'do_ri':
arch/score/kernel/traps.c:248:4: error: implicit declaration of function 'user_disable_single_step'
arch/score/mm/extable.c: In function 'fixup_exception':
arch/score/mm/extable.c:32:38: error: dereferencing pointer to incomplete type
arch/score/mm/extable.c:34:24: error: dereferencing pointer to incomplete type
because extable.h doesn't drag in the same amount of headers as the
module.h did. Add in the headers which were implicitly expected.
Fixes:
90858794c960 ("module.h: remove extable.h include now users have migrated")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
[PG: tweak commit log; refresh for sched header refactoring.]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Linus Torvalds [Sat, 11 Mar 2017 08:20:12 +0000 (00:20 -0800)]
Merge tag 'tty-4.11-rc2' of git://git./linux/kernel/git/gregkh/tty
Pull tty/serial fixes frpm Greg KH:
"Here are two bugfixes for tty stuff for 4.11-rc2.
One of them resolves the pretty bad bug in the n_hdlc code that
Alexander Popov found and fixed and has been reported everywhere. The
other just fixes a samsung serial driver issue when DMA fails on some
systems.
Both have been in linux-next with no reported issues"
* tag 'tty-4.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
serial: samsung: Continue to work if DMA request fails
tty: n_hdlc: get rid of racy n_hdlc.tbuf
Linus Torvalds [Sat, 11 Mar 2017 08:13:28 +0000 (00:13 -0800)]
Merge tag 'staging-4.11-rc2' of git://git./linux/kernel/git/gregkh/staging
Pull staging driver fixes from Greg KH:
"Here are two small build warning fixes for some staging drivers that
Arnd has found on his valiant quest to get the kernel to build
properly with no warnings.
Both of these have been in linux-next this week and resolve the
reported issues"
* tag 'staging-4.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
staging: octeon: remove unused variable
staging/vc04_services: add CONFIG_OF dependency
Linus Torvalds [Sat, 11 Mar 2017 08:08:39 +0000 (00:08 -0800)]
Merge tag 'usb-4.11-rc2' of git://git./linux/kernel/git/gregkh/usb
Pull USB fixes from Greg KH:
"Here is a number of different USB fixes for 4.11-rc2.
Seems like there were a lot of unresolved issues that people have been
finding for this subsystem, and a bunch of good security auditing
happening as well from Johan Hovold. There's the usual batch of gadget
driver fixes and xhci issues resolved as well.
All of these have been in linux-next with no reported issues"
* tag 'usb-4.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (35 commits)
usb: host: xhci-plat: Fix timeout on removal of hot pluggable xhci controllers
usb: host: xhci-dbg: HCIVERSION should be a binary number
usb: xhci: remove dummy extra_priv_size for size of xhci_hcd struct
usb: xhci-mtk: check hcc_params after adding primary hcd
USB: serial: digi_acceleport: fix OOB-event processing
MAINTAINERS: usb251xb: remove reference inexistent file
doc: dt-bindings: usb251xb: mark reg as required
usb: usb251xb: dt: add unit suffix to oc-delay and power-on-time
usb: usb251xb: remove max_{power,current}_{sp,bp} properties
usb-storage: Add ignore-residue quirk for Initio INIC-3619
USB: iowarrior: fix NULL-deref in write
USB: iowarrior: fix NULL-deref at probe
usb: phy: isp1301: Add OF device ID table
usb: ohci-at91: Do not drop unhandled USB suspend control requests
USB: serial: safe_serial: fix information leak in completion handler
USB: serial: io_ti: fix information leak in completion handler
USB: serial: omninet: drop open callback
USB: serial: omninet: fix reference leaks at open
USB: serial: io_ti: fix NULL-deref in interrupt callback
usb: dwc3: gadget: make to increment req->remaining in all cases
...
Linus Torvalds [Sat, 11 Mar 2017 08:06:18 +0000 (00:06 -0800)]
Merge tag 'pinctrl-v4.11-2' of git://git./linux/kernel/git/linusw/linux-pinctrl
Pull pinctrl fixes from Linus Walleij:
"Two smaller pin control fixes for the v4.11 series:
- Add a get_direction() function to the qcom driver
- Fix two pin names in the uniphier driver"
* tag 'pinctrl-v4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
pinctrl: uniphier: change pin names of aio/xirq for LD11
pinctrl: qcom: add get_direction function
Thomas Gleixner [Fri, 10 Mar 2017 12:17:18 +0000 (13:17 +0100)]
kexec, x86/purgatory: Unbreak it and clean it up
The purgatory code defines global variables which are referenced via a
symbol lookup in the kexec code (core and arch).
A recent commit addressing sparse warnings made these static and thereby
broke kexec_file.
Why did this happen? Simply because the whole machinery is undocumented and
lacks any form of forward declarations. The variable names are unspecific
and lack a prefix, so adding forward declarations creates shadow variables
in the core code. Aside of that the code relies on magic constants and
duplicate struct definitions with no way to ensure that these things stay
in sync. The section placement of the purgatory variables happened by
chance and not by design.
Unbreak kexec and cleanup the mess:
- Add proper forward declarations and document the usage
- Use common struct definition
- Use the proper common defines instead of magic constants
- Add a purgatory_ prefix to have a proper name space
- Use ARRAY_SIZE() instead of a homebrewn reimplementation
- Add proper sections to the purgatory variables [ From Mike ]
Fixes:
72042a8c7b01 ("x86/purgatory: Make functions and variables static")
Reported-by: Mike Galbraith <<efault@gmx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Nicholas Mc Guire <der.herr@hofr.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: "Tobin C. Harding" <me@tobin.cc>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1703101315140.3681@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Linus Torvalds [Fri, 10 Mar 2017 19:05:47 +0000 (11:05 -0800)]
Merge tag 'ceph-for-4.11-rc2' of git://github.com/ceph/ceph-client
Pull ceph fixes from Ilya Dryomov:
- a fix for the recently discovered misdirected requests bug present in
jewel and later on the server side and all stable kernels
- a fixup for -rc1 CRUSH changes
- two usability enhancements: osd_request_timeout option and
supported_features bus attribute.
* tag 'ceph-for-4.11-rc2' of git://github.com/ceph/ceph-client:
libceph: osd_request_timeout option
rbd: supported_features bus attribute
libceph: don't set weight to IN when OSD is destroyed
libceph: fix crush_decode() for older maps
Linus Torvalds [Fri, 10 Mar 2017 17:56:16 +0000 (09:56 -0800)]
Merge branch 'i2c/for-current' of git://git./linux/kernel/git/wsa/linux
Pull i2c fixes from Wolfram Sang:
"Here are some driver bugfixes from I2C.
Unusual this time are the two reverts. One because I accidently picked
a patch from the list which I should have pulled from my co-maintainer
instead ("missing of_node_put"). And one which I wrongly assumed to be
an easy fix but it turned out already that it needs more iterations
("copy device properties")"
* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
Revert "i2c: copy device properties when using i2c_register_board_info()"
Revert "i2c: add missing of_node_put in i2c_mux_del_adapters"
i2c: exynos5: Avoid transaction timeouts due TRANSFER_DONE_AUTO not set
i2c: designware: add reset interface
i2c: meson: fix wrong variable usage in meson_i2c_put_data
i2c: copy device properties when using i2c_register_board_info()
i2c: m65xx: drop superfluous quirk structure
i2c: brcmstb: Fix START and STOP conditions
i2c: add missing of_node_put in i2c_mux_del_adapters
i2c: riic: fix restart condition
i2c: add missing of_node_put in i2c_mux_del_adapters
Linus Torvalds [Fri, 10 Mar 2017 17:53:00 +0000 (09:53 -0800)]
Merge tag 'drm-fixes-for-4.11-rc2' of git://people.freedesktop.org/~airlied/linux
Pull drm fixes from Dave Airlie:
"Intel, amd and mxsfb fixes.
These are the drm fixes I've collected for rc2. Mostly i915 GVT only
fixes, along with a single EDID fix, some mxsfb fixes and a few minor
amd fixes"
* tag 'drm-fixes-for-4.11-rc2' of git://people.freedesktop.org/~airlied/linux: (38 commits)
drm: mxsfb: Implement drm_panel handling
drm: mxsfb_crtc: Fix the framebuffer misplacement
drm: mxsfb: Fix crash when provided invalid DT bindings
drm: mxsfb: fix pixel clock polarity
drm: mxsfb: use bus_format to determine LCD bus width
drm/amdgpu: bump driver version for some new features
drm/amdgpu: validate paramaters in the gem ioctl
drm/amd/amdgpu: fix console deadlock if late init failed
drm/i915/gvt: change some gvt_err to gvt_dbg_cmd
drm/i915/gvt: protect RO and Rsvd bits of virtual vgpu configuration space
drm/i915/gvt: handle workload lifecycle properly
drm/edid: Add EDID_QUIRK_FORCE_8BPC quirk for Rotel RSX-1058
drm/i915/gvt: fix an error for F_RO flag
drm/i915/gvt: use pfn_valid for better checking
drm/i915/gvt: set SFUSE_STRAP properly for vitual monitor detection
drm/i915/gvt: fix an error for one register
drm/i915/gvt: add more registers into handlers list
drm/i915/gvt: have more registers with F_CMD_ACCESS flags set
drm/i915/gvt: add some new MMIOs to cmd_access white list
drm/i915/gvt: fix pcode mailbox write emulation of BDW
...
Linus Torvalds [Fri, 10 Mar 2017 16:59:07 +0000 (08:59 -0800)]
Merge branch 'prep-for-5level'
Merge 5-level page table prep from Kirill Shutemov:
"Here's relatively low-risk part of 5-level paging patchset. Merging it
now will make x86 5-level paging enabling in v4.12 easier.
The first patch is actually x86-specific: detect 5-level paging
support. It boils down to single define.
The rest of patchset converts Linux MMU abstraction from 4- to 5-level
paging.
Enabling of new abstraction in most cases requires adding single line
of code in arch-specific code. The rest is taken care by asm-generic/.
Changes to mm/ code are mostly mechanical: add support for new page
table level -- p4d_t -- where we deal with pud_t now.
v2:
- fix build on microblaze (Michal);
- comment for __ARCH_HAS_5LEVEL_HACK in kasan_populate_zero_shadow();
- acks from Michal"
* emailed patches from Kirill A Shutemov <kirill.shutemov@linux.intel.com>:
mm: introduce __p4d_alloc()
mm: convert generic code to 5-level paging
asm-generic: introduce <asm-generic/pgtable-nop4d.h>
arch, mm: convert all architectures to use 5level-fixup.h
asm-generic: introduce __ARCH_USE_5LEVEL_HACK
asm-generic: introduce 5level-fixup.h
x86/cpufeature: Add 5-level paging detection
Linus Torvalds [Fri, 10 Mar 2017 16:34:42 +0000 (08:34 -0800)]
Merge branch 'akpm' (patches from Andrew)
Merge fixes from Andrew Morton:
"26 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (26 commits)
userfaultfd: remove wrong comment from userfaultfd_ctx_get()
fat: fix using uninitialized fields of fat_inode/fsinfo_inode
sh: cayman: IDE support fix
kasan: fix races in quarantine_remove_cache()
kasan: resched in quarantine_remove_cache()
mm: do not call mem_cgroup_free() from within mem_cgroup_alloc()
thp: fix another corner case of munlock() vs. THPs
rmap: fix NULL-pointer dereference on THP munlocking
mm/memblock.c: fix memblock_next_valid_pfn()
userfaultfd: selftest: vm: allow to build in vm/ directory
userfaultfd: non-cooperative: userfaultfd_remove revalidate vma in MADV_DONTNEED
userfaultfd: non-cooperative: fix fork fctx->new memleak
mm/cgroup: avoid panic when init with low memory
drivers/md/bcache/util.h: remove duplicate inclusion of blkdev.h
mm/vmstats: add thp_split_pud event for clarity
include/linux/fs.h: fix unsigned enum warning with gcc-4.2
userfaultfd: non-cooperative: release all ctx in dup_userfaultfd_complete
userfaultfd: non-cooperative: robustness check
userfaultfd: non-cooperative: rollback userfaultfd_exit
x86, mm: unify exit paths in gup_pte_range()
...
Matjaz Hegedic [Thu, 9 Mar 2017 13:00:17 +0000 (14:00 +0100)]
x86/reboot/quirks: Fix typo in ASUS EeeBook X205TA reboot quirk
The reboot quirk for ASUS EeeBook X205TA contains a typo in
DMI_PRODUCT_NAME, improperly referring to X205TAW instead of
X205TA, which prevents the quirk from being triggered. The
model X205TAW already has a reboot quirk of its own.
This fix simply removes the inappropriate final letter W.
Fixes:
90b28ded88dd ("x86/reboot/quirks: Add ASUS EeeBook X205TA reboot quirk")
Signed-off-by: Matjaz Hegedic <matjaz.hegedic@gmail.com>
Link: http://lkml.kernel.org/r/1489064417-7445-1-git-send-email-matjaz.hegedic@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Linus Torvalds [Fri, 10 Mar 2017 02:11:28 +0000 (18:11 -0800)]
Merge tag 'xfs-4.11-fixes-1' of git://git./fs/xfs/xfs-linux
Pull xfs fixes from Darrick Wong:
"Here are some bug fixes for -rc2 to clean up the copy on write
handling and to remove a cause of hangs.
- Fix various iomap bugs
- Fix overly aggressive CoW preallocation garbage collection
- Fixes to CoW endio error handling
- Fix some incorrect geometry calculations
- Remove a potential system hang in bulkstat
- Try to allocate blocks more aggressively to reduce ENOSPC errors"
* tag 'xfs-4.11-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: try any AG when allocating the first btree block when reflinking
xfs: use iomap new flag for newly allocated delalloc blocks
xfs: remove kmem_zalloc_greedy
xfs: Use xfs_icluster_size_fsb() to calculate inode alignment mask
xfs: fix and streamline error handling in xfs_end_io
xfs: only reclaim unwritten COW extents periodically
iomap: invalidate page caches should be after iomap_dio_complete() in direct write
Linus Torvalds [Fri, 10 Mar 2017 02:05:41 +0000 (18:05 -0800)]
Merge tag 'gcc-plugins-v4.11-rc2' of git://git./linux/kernel/git/kees/linux
Pull gcc-plugins fix from Kees Cook:
"Fixes a typo in sancov plugin, exposed in earlier compiler versions"
* tag 'gcc-plugins-v4.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
gcc-plugins: fix sancov_plugin for gcc-5
Fabio Estevam [Wed, 1 Feb 2017 17:19:47 +0000 (15:19 -0200)]
drm: mxsfb: Implement drm_panel handling
Currently when the 'power-supply' regulator is passed via device tree
it does not actually work since drm_panel_prepare()/drm_panel_enable()
are never called.
Quoting Thierry Reding: "It should really call drm_panel_prepare() and
drm_panel_enable() while switching on the display pipeline and
drm_panel_disable(), followed by drm_panel_unprepare() while switching
off the display pipeline."
So do as suggested, so that the 'power-supply' regulator can be functional.
Reported-by: Breno Lima <breno.lima@nxp.com>
Suggested-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Tested-by: Marek Vasut <marex@denx.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Fabio Estevam [Thu, 2 Feb 2017 21:26:38 +0000 (19:26 -0200)]
drm: mxsfb_crtc: Fix the framebuffer misplacement
Currently the framebuffer content is displayed with incorrect offsets
in both the vertical and horizontal directions.
The fbdev version of the driver does not show this problem. Breno Lima
dumped the eLCDIF controller registers on both the drm and fbdev drivers
and noticed that the VDCTRL3 register is configured incorrectly in the
drm driver.
The fbdev driver calculates the vertical and horizontal wait counts
of the VDCTRL3 register by doing: back porch + sync length.
Looking at the horizontal and vertical timing diagram from
include/drm/drm_modes.h this value corresponds to:
crtc_[hv]total - crtc_[hv]sync_start
So fix the VDCTRL3 register setting accordingly so that the eLCDIF
controller can properly show the framebuffer content in the correct
position.
Reported-by: Breno Lima <breno.lima@nxp.com>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Tested-by: Breno Lima <breno.lima@nxp.com>
Tested-by: Marek Vasut <marex@denx.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Marek Vasut [Sat, 28 Jan 2017 17:01:57 +0000 (18:01 +0100)]
drm: mxsfb: Fix crash when provided invalid DT bindings
The mxsfb driver will crash if the mxsfb DT node has a subnode,
but the content of the subnode is not of-graph binding with an
endpoint linking to panel. The crash was triggered by providing
old-style panel bindings to the mxsfb driver instead of the new
of-graph ones.
The problem happens in mxsfb_create_output(), which is invoked
from mxsfb_load(). The mxsfb_create_output() iterates over all
mxsfb DT subnode endpoints and tries to bind a panel on each
endpoint. If there is any problem binding the panel, that is,
mxsfb->panel == NULL, this function will return an error code,
otherwise success 0 is returned.
If the subnodes do not specify of-graph binding with an endpoint,
the iteration over endpoints in mxsfb_create_output() will have
zero cycles and the function will immediatelly return 0, but the
mxsfb->panel will remain NULL. This is propagated back into the
mxsfb_load(), which does not detect any problem and expects that
the mxsfb->panel is valid, thus calls mxsfb_panel_attach(). But
since mxsfb->panel == NULL, mxsfb_panel_attach() is called with
first argument NULL and this crashes the kernel.
This patch fixes the problem by explicitly checking for valid
mxsfb->panel at the end of the iteration in mxsfb_create_output().
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Breno Matheus Lima <brenomatheus@gmail.com>
Tested-by: Breno Lima <breno.lima@nxp.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Stefan Agner [Wed, 14 Dec 2016 20:48:09 +0000 (12:48 -0800)]
drm: mxsfb: fix pixel clock polarity
The DRM subsystem specifies the pixel clock polarity from a
controllers perspective: DRM_BUS_FLAG_PIXDATA_NEGEDGE means
the controller drives the data on pixel clocks falling edge.
That is the controllers DOTCLK_POL=0 (Default is data launched
at negative edge).
Also change the data enable logic to be high active by default
and only change if explicitly requested via bus_flags. With
that defaults are:
- Data enable: high active
- Pixel clock polarity: controller drives data on negative edge
Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Stefan Agner [Thu, 15 Dec 2016 01:28:41 +0000 (17:28 -0800)]
drm: mxsfb: use bus_format to determine LCD bus width
The LCD bus width does not need to align with the pixel format. The
LCDIF controller automatically converts between pixel formats and
bus width by padding or dropping LSBs.
The DRM subsystem has the notion of bus_format which allows to
determine what bus_formats are supported by the display. Choose the
first available or fallback to 24 bit if none are available.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Dave Airlie [Fri, 10 Mar 2017 01:07:34 +0000 (11:07 +1000)]
Merge branch 'drm-fixes-4.11' of git://people.freedesktop.org/~agd5f/linux into drm-fixes
* 'drm-fixes-4.11' of git://people.freedesktop.org/~agd5f/linux:
drm/amdgpu: bump driver version for some new features
drm/amdgpu: validate paramaters in the gem ioctl
drm/amd/amdgpu: fix console deadlock if late init failed
Dave Airlie [Fri, 10 Mar 2017 01:07:13 +0000 (11:07 +1000)]
Merge tag 'drm-intel-fixes-2017-03-09' of git://anongit.freedesktop.org/git/drm-intel into drm-fixes
flushing out gvt-g fixes
* tag 'drm-intel-fixes-2017-03-09' of git://anongit.freedesktop.org/git/drm-intel: (29 commits)
drm/i915/gvt: change some gvt_err to gvt_dbg_cmd
drm/i915/gvt: protect RO and Rsvd bits of virtual vgpu configuration space
drm/i915/gvt: handle workload lifecycle properly
drm/i915/gvt: fix an error for F_RO flag
drm/i915/gvt: use pfn_valid for better checking
drm/i915/gvt: set SFUSE_STRAP properly for vitual monitor detection
drm/i915/gvt: fix an error for one register
drm/i915/gvt: add more registers into handlers list
drm/i915/gvt: have more registers with F_CMD_ACCESS flags set
drm/i915/gvt: add some new MMIOs to cmd_access white list
drm/i915/gvt: fix pcode mailbox write emulation of BDW
drm/i915/gvt: add resolution definition for vGPU type
drm/i915/gvt: Add more edid definition support
drm/i915/gvt: adjust to fixed vGPU types
drm/i915/gvt: remove unnecessary error msg from gtt write
drm/i915/gvt: refine pcode write emulation
drm/i915/gvt: clear the vGPU reset logic
drm/i915/gvt: decrease priority of output msg for untracked mmio
drm/i915/gvt: set default value to 0 for unhandled mmio regs
drm/i915/gvt: add cmd_access to GEN7_HALF_SLICE_CHICKEN1
...
Dave Airlie [Fri, 10 Mar 2017 01:06:46 +0000 (11:06 +1000)]
Merge tag 'drm-misc-fixes-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-fixes
Just 1 8bpc quirk from Ville, cc: stable
* tag 'drm-misc-fixes-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc:
drm/edid: Add EDID_QUIRK_FORCE_8BPC quirk for Rotel RSX-1058
David Hildenbrand [Fri, 10 Mar 2017 00:17:40 +0000 (16:17 -0800)]
userfaultfd: remove wrong comment from userfaultfd_ctx_get()
It's a void function, so there is no return value;
Link: http://lkml.kernel.org/r/20170309150817.7510-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
OGAWA Hirofumi [Fri, 10 Mar 2017 00:17:37 +0000 (16:17 -0800)]
fat: fix using uninitialized fields of fat_inode/fsinfo_inode
Recently fallocate patch was merged and it uses
MSDOS_I(inode)->mmu_private at fat_evict_inode(). However,
fat_inode/fsinfo_inode that was introduced in past didn't initialize
MSDOS_I(inode) properly.
With those combinations, it became the cause of accessing random entry
in FAT area.
Link: http://lkml.kernel.org/r/87pohrj4i8.fsf@mail.parknet.co.jp
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reported-by: Moreno Bartalucci <moreno.bartalucci@tecnorama.it>
Tested-by: Moreno Bartalucci <moreno.bartalucci@tecnorama.it>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bartlomiej Zolnierkiewicz [Fri, 10 Mar 2017 00:17:34 +0000 (16:17 -0800)]
sh: cayman: IDE support fix
Remove incorrect CONFIG_IDE ifdef (CONFIG_IDE config option is for
internal drivers/ide/ use) and make IDE hardware interface always
initialized (not only when IDE subsystem is built-in).
This patch allows Cayman board to work with modular IDE subsystem
support and removes the requirement of having the whole core IDE
subsystem built-in when using libata PATA support.
Link: http://lkml.kernel.org/r/1990884.yFoE6lSB9G@amdc3058
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dmitry Vyukov [Fri, 10 Mar 2017 00:17:32 +0000 (16:17 -0800)]
kasan: fix races in quarantine_remove_cache()
quarantine_remove_cache() frees all pending objects that belong to the
cache, before we destroy the cache itself. However there are currently
two possibilities how it can fail to do so.
First, another thread can hold some of the objects from the cache in
temp list in quarantine_put(). quarantine_put() has a windows of
enabled interrupts, and on_each_cpu() in quarantine_remove_cache() can
finish right in that window. These objects will be later freed into the
destroyed cache.
Then, quarantine_reduce() has the same problem. It grabs a batch of
objects from the global quarantine, then unlocks quarantine_lock and
then frees the batch. quarantine_remove_cache() can finish while some
objects from the cache are still in the local to_free list in
quarantine_reduce().
Fix the race with quarantine_put() by disabling interrupts for the whole
duration of quarantine_put(). In combination with on_each_cpu() in
quarantine_remove_cache() it ensures that quarantine_remove_cache()
either sees the objects in the per-cpu list or in the global list.
Fix the race with quarantine_reduce() by protecting quarantine_reduce()
with srcu critical section and then doing synchronize_srcu() at the end
of quarantine_remove_cache().
I've done some assessment of how good synchronize_srcu() works in this
case. And on a 4 CPU VM I see that it blocks waiting for pending read
critical sections in about 2-3% of cases. Which looks good to me.
I suspect that these races are the root cause of some GPFs that I
episodically hit. Previously I did not have any explanation for them.
BUG: unable to handle kernel NULL pointer dereference at
00000000000000c8
IP: qlist_free_all+0x2e/0xc0 mm/kasan/quarantine.c:155
PGD
6aeea067
PUD
60ed7067
PMD 0
Oops: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 13667 Comm: syz-executor2 Not tainted 4.10.0+ #60
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task:
ffff88005f948040 task.stack:
ffff880069818000
RIP: 0010:qlist_free_all+0x2e/0xc0 mm/kasan/quarantine.c:155
RSP: 0018:
ffff88006981f298 EFLAGS:
00010246
RAX:
ffffea0000ffff00 RBX:
0000000000000000 RCX:
ffffea0000ffff1f
RDX:
0000000000000000 RSI:
ffff88003fffc3e0 RDI:
0000000000000000
RBP:
ffff88006981f2c0 R08:
ffff88002fed7bd8 R09:
00000001001f000d
R10:
00000000001f000d R11:
ffff88006981f000 R12:
ffff88003fffc3e0
R13:
ffff88006981f2d0 R14:
ffffffff81877fae R15:
0000000080000000
FS:
00007fb911a2d700(0000) GS:
ffff88003ec00000(0000) knlGS:
0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
CR2:
00000000000000c8 CR3:
0000000060ed6000 CR4:
00000000000006f0
Call Trace:
quarantine_reduce+0x10e/0x120 mm/kasan/quarantine.c:239
kasan_kmalloc+0xca/0xe0 mm/kasan/kasan.c:590
kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:544
slab_post_alloc_hook mm/slab.h:456 [inline]
slab_alloc_node mm/slub.c:2718 [inline]
kmem_cache_alloc_node+0x1d3/0x280 mm/slub.c:2754
__alloc_skb+0x10f/0x770 net/core/skbuff.c:219
alloc_skb include/linux/skbuff.h:932 [inline]
_sctp_make_chunk+0x3b/0x260 net/sctp/sm_make_chunk.c:1388
sctp_make_data net/sctp/sm_make_chunk.c:1420 [inline]
sctp_make_datafrag_empty+0x208/0x360 net/sctp/sm_make_chunk.c:746
sctp_datamsg_from_user+0x7e8/0x11d0 net/sctp/chunk.c:266
sctp_sendmsg+0x2611/0x3970 net/sctp/socket.c:1962
inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:761
sock_sendmsg_nosec net/socket.c:633 [inline]
sock_sendmsg+0xca/0x110 net/socket.c:643
SYSC_sendto+0x660/0x810 net/socket.c:1685
SyS_sendto+0x40/0x50 net/socket.c:1653
I am not sure about backporting. The bug is quite hard to trigger, I've
seen it few times during our massive continuous testing (however, it
could be cause of some other episodic stray crashes as it leads to
memory corruption...). If it is triggered, the consequences are very
bad -- almost definite bad memory corruption. The fix is non trivial
and has chances of introducing new bugs. I am also not sure how
actively people use KASAN on older releases.
[dvyukov@google.com: - sorted includes[
Link: http://lkml.kernel.org/r/20170309094028.51088-1-dvyukov@google.com
Link: http://lkml.kernel.org/r/20170308151532.5070-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dmitry Vyukov [Fri, 10 Mar 2017 00:17:28 +0000 (16:17 -0800)]
kasan: resched in quarantine_remove_cache()
We see reported stalls/lockups in quarantine_remove_cache() on machines
with large amounts of RAM. quarantine_remove_cache() needs to scan
whole quarantine in order to take out all objects belonging to the
cache. Quarantine is currently 1/32-th of RAM, e.g. on a machine with
256GB of memory that will be 8GB. Moreover quarantine scanning is a
walk over uncached linked list, which is slow.
Add cond_resched() after scanning of each non-empty batch of objects.
Batches are specifically kept of reasonable size for quarantine_put().
On a machine with 256GB of RAM we should have ~512 non-empty batches,
each with 16MB of objects.
Link: http://lkml.kernel.org/r/20170308154239.25440-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tahsin Erdogan [Fri, 10 Mar 2017 00:17:26 +0000 (16:17 -0800)]
mm: do not call mem_cgroup_free() from within mem_cgroup_alloc()
mem_cgroup_free() indirectly calls wb_domain_exit() which is not
prepared to deal with a struct wb_domain object that hasn't executed
wb_domain_init(). For instance, the following warning message is
printed by lockdep if alloc_percpu() fails in mem_cgroup_alloc():
INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 1 PID: 1950 Comm: mkdir Not tainted 4.10.0+ #151
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
dump_stack+0x67/0x99
register_lock_class+0x36d/0x540
__lock_acquire+0x7f/0x1a30
lock_acquire+0xcc/0x200
del_timer_sync+0x3c/0xc0
wb_domain_exit+0x14/0x20
mem_cgroup_free+0x14/0x40
mem_cgroup_css_alloc+0x3f9/0x620
cgroup_apply_control_enable+0x190/0x390
cgroup_mkdir+0x290/0x3d0
kernfs_iop_mkdir+0x58/0x80
vfs_mkdir+0x10e/0x1a0
SyS_mkdirat+0xa8/0xd0
SyS_mkdir+0x14/0x20
entry_SYSCALL_64_fastpath+0x18/0xad
Add __mem_cgroup_free() which skips wb_domain_exit(). This is used by
both mem_cgroup_free() and mem_cgroup_alloc() clean up.
Fixes:
0b8f73e104285 ("mm: memcontrol: clean up alloc, online, offline, free functions")
Link: http://lkml.kernel.org/r/20170306192122.24262-1-tahsin@google.com
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kirill A. Shutemov [Fri, 10 Mar 2017 00:17:23 +0000 (16:17 -0800)]
thp: fix another corner case of munlock() vs. THPs
The following test case triggers BUG() in munlock_vma_pages_range():
int main(int argc, char *argv[])
{
int fd;
system("mount -t tmpfs -o huge=always none /mnt");
fd = open("/mnt/test", O_CREAT | O_RDWR);
ftruncate(fd, 4UL << 20);
mmap(NULL, 4UL << 20, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_FIXED | MAP_LOCKED, fd, 0);
mmap(NULL, 4096, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_LOCKED, fd, 0);
munlockall();
return 0;
}
The second mmap() create PTE-mapping of the first huge page in file. It
makes kernel munlock the page as we never keep PTE-mapped page mlocked.
On munlockall() when we handle vma created by the first mmap(),
munlock_vma_page() returns page_mask == 0, as the page is not mlocked
anymore. On next iteration follow_page_mask() return tail page, but
page_mask is HPAGE_NR_PAGES - 1. It makes us skip to the first tail
page of the next huge page and step on
VM_BUG_ON_PAGE(PageMlocked(page)).
The fix is not use the page_mask from follow_page_mask() at all. It has
no use for us.
Link: http://lkml.kernel.org/r/20170302150252.34120-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org> [4.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kirill A. Shutemov [Fri, 10 Mar 2017 00:17:20 +0000 (16:17 -0800)]
rmap: fix NULL-pointer dereference on THP munlocking
The following test case triggers NULL-pointer derefernce in
try_to_unmap_one():
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
int main(int argc, char *argv[])
{
int fd;
system("mount -t tmpfs -o huge=always none /mnt");
fd = open("/mnt/test", O_CREAT | O_RDWR);
ftruncate(fd, 2UL << 20);
mmap(NULL, 2UL << 20, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_FIXED | MAP_LOCKED, fd, 0);
mmap(NULL, 2UL << 20, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_LOCKED, fd, 0);
munlockall();
return 0;
}
Apparently, there's a case when we call try_to_unmap() on huge PMDs:
it's TTU_MUNLOCK.
Let's handle this case correctly.
Fixes:
c7ab0d2fdc84 ("mm: convert try_to_unmap_one() to use page_vma_mapped_walk()")
Link: http://lkml.kernel.org/r/20170302151159.30592-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
AKASHI Takahiro [Fri, 10 Mar 2017 00:17:17 +0000 (16:17 -0800)]
mm/memblock.c: fix memblock_next_valid_pfn()
Obviously, we should not access memblock.memory.regions[right] if
'right' is outside of [0..memblock.memory.cnt>.
Fixes:
b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns where possible")
Link: http://lkml.kernel.org/r/20170303023745.9104-1-takahiro.akashi@linaro.org
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrea Arcangeli [Fri, 10 Mar 2017 00:17:14 +0000 (16:17 -0800)]
userfaultfd: selftest: vm: allow to build in vm/ directory
linux/tools/testing/selftests/vm $ make
gcc -Wall -I ../../../../usr/include compaction_test.c -lrt -o /compaction_test
/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.4/../../../../x86_64-pc-linux-gnu/bin/ld: cannot open output file /compaction_test: Permission denied
collect2: error: ld returned 1 exit status
make: *** [../lib.mk:54: /compaction_test] Error 1
Since commit
a8ba798bc8ec ("selftests: enable O and KBUILD_OUTPUT")
selftests/vm build fails if run from the "selftests/vm" directory, but
it works in the selftests/ directory. It's quicker to be able to do a
local vm-only build after a tree wipe and this patch allows for it
again.
Link: http://lkml.kernel.org/r/20170302173738.18994-4-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrea Arcangeli [Fri, 10 Mar 2017 00:17:11 +0000 (16:17 -0800)]
userfaultfd: non-cooperative: userfaultfd_remove revalidate vma in MADV_DONTNEED
userfaultfd_remove() has to be execute before zapping the pagetables or
UFFDIO_COPY could keep filling pages after zap_page_range returned,
which would result in non zero data after a MADV_DONTNEED.
However userfaultfd_remove() may have to release the mmap_sem. This was
handled correctly in MADV_REMOVE, but MADV_DONTNEED accessed a
potentially stale vma (the very vma passed to zap_page_range(vma, ...)).
The fix consists in revalidating the vma in case userfaultfd_remove()
had to release the mmap_sem.
This also optimizes away an unnecessary down_read/up_read in the
MADV_REMOVE case if UFFD_EVENT_FORK had to be delivered.
It all remains zero runtime cost in case CONFIG_USERFAULTFD=n as
userfaultfd_remove() will be defined as "true" at build time.
Link: http://lkml.kernel.org/r/20170302173738.18994-3-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Rapoport [Fri, 10 Mar 2017 00:17:09 +0000 (16:17 -0800)]
userfaultfd: non-cooperative: fix fork fctx->new memleak
We have a memleak in the ->new ctx if the uffd of the parent is closed
before the fork event is read, nothing frees the new context.
Link: http://lkml.kernel.org/r/20170302173738.18994-2-aarcange@redhat.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Laurent Dufour [Fri, 10 Mar 2017 00:17:06 +0000 (16:17 -0800)]
mm/cgroup: avoid panic when init with low memory
The system may panic when initialisation is done when almost all the
memory is assigned to the huge pages using the kernel command line
parameter hugepage=xxxx. Panic may occur like this:
Unable to handle kernel paging request for data at address 0x00000000
Faulting instruction address: 0xc000000000302b88
Oops: Kernel access of bad area, sig: 11 [#1]
SMP NR_CPUS=2048 [ 0.082424] NUMA
pSeries
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.9.0-15-generic #16-Ubuntu
task:
c00000021ed01600 task.stack:
c00000010d108000
NIP:
c000000000302b88 LR:
c000000000270e04 CTR:
c00000000016cfd0
REGS:
c00000010d10b2c0 TRAP: 0300 Not tainted (4.9.0-15-generic)
MSR:
8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE>[ 0.082770] CR:
28424422 XER:
00000000
CFAR:
c0000000003d28b8 DAR:
0000000000000000 DSISR:
40000000 SOFTE: 1
GPR00:
c000000000270e04 c00000010d10b540 c00000000141a300 c00000010fff6300
GPR04:
0000000000000000 00000000026012c0 c00000010d10b630 0000000487ab0000
GPR08:
000000010ee90000 c000000001454fd8 0000000000000000 0000000000000000
GPR12:
0000000000004400 c00000000fb80000 00000000026012c0 00000000026012c0
GPR16:
00000000026012c0 0000000000000000 0000000000000000 0000000000000002
GPR20:
000000000000000c 0000000000000000 0000000000000000 00000000024200c0
GPR24:
c0000000016eef48 0000000000000000 c00000010fff7d00 00000000026012c0
GPR28:
0000000000000000 c00000010fff7d00 c00000010fff6300 c00000010d10b6d0
NIP mem_cgroup_soft_limit_reclaim+0xf8/0x4f0
LR do_try_to_free_pages+0x1b4/0x450
Call Trace:
do_try_to_free_pages+0x1b4/0x450
try_to_free_pages+0xf8/0x270
__alloc_pages_nodemask+0x7a8/0xff0
new_slab+0x104/0x8e0
___slab_alloc+0x620/0x700
__slab_alloc+0x34/0x60
kmem_cache_alloc_node_trace+0xdc/0x310
mem_cgroup_init+0x158/0x1c8
do_one_initcall+0x68/0x1d0
kernel_init_freeable+0x278/0x360
kernel_init+0x24/0x170
ret_from_kernel_thread+0x5c/0x74
Instruction dump:
eb81ffe0 eba1ffe8 ebc1fff0 ebe1fff8 4e800020 3d230001 e9499a42 3d220004
3929acd8 794a1f24 7d295214 eac90100 <
e9360000>
2fa90000 419eff74 3b200000
---[ end trace
342f5208b00d01b6 ]---
This is a chicken and egg issue where the kernel try to get free memory
when allocating per node data in mem_cgroup_init(), but in that path
mem_cgroup_soft_limit_reclaim() is called which assumes that these data
are allocated.
As mem_cgroup_soft_limit_reclaim() is best effort, it should return when
these data are not yet allocated.
This patch also fixes potential null pointer access in
mem_cgroup_remove_from_trees() and mem_cgroup_update_tree().
Link: http://lkml.kernel.org/r/1487856999-16581-2-git-send-email-ldufour@linux.vnet.ibm.com
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Masanari Iida [Fri, 10 Mar 2017 00:17:03 +0000 (16:17 -0800)]
drivers/md/bcache/util.h: remove duplicate inclusion of blkdev.h
Link: http://lkml.kernel.org/r/20170226060230.11555-1-standby24x7@gmail.com
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Coly Li <colyli@suse.de>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Yisheng Xie [Fri, 10 Mar 2017 00:17:00 +0000 (16:17 -0800)]
mm/vmstats: add thp_split_pud event for clarity
We added support for PUD-sized transparent hugepages, however we count
the event "thp split pud" into thp_split_pmd event.
To separate the event count of thp split pud from pmd, add a new event
named thp_split_pud.
Link: http://lkml.kernel.org/r/1488282380-5076-1-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Arnd Bergmann [Fri, 10 Mar 2017 00:16:57 +0000 (16:16 -0800)]
include/linux/fs.h: fix unsigned enum warning with gcc-4.2
With arm-linux-gcc-4.2, almost every file we build in the kernel ends up
with this warning:
include/linux/fs.h:2648: warning: comparison of unsigned expression < 0 is always false
Later versions don't have this problem, but it's easy enough to work
around.
Link: http://lkml.kernel.org/r/20161216105634.235457-12-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrea Arcangeli [Fri, 10 Mar 2017 00:16:54 +0000 (16:16 -0800)]
userfaultfd: non-cooperative: release all ctx in dup_userfaultfd_complete
Don't stop running dup_fctx() even if userfaultfd_event_wait_completion
fails as it has to run userfaultfd_ctx_put on all ctx to pair against
the userfaultfd_ctx_get that was run on all fctx->orig in
dup_userfaultfd.
Link: http://lkml.kernel.org/r/20170224181957.19736-4-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrea Arcangeli [Fri, 10 Mar 2017 00:16:52 +0000 (16:16 -0800)]
userfaultfd: non-cooperative: robustness check
Similar to the handle_userfault() case, also make sure to never attempt
to send any event past the PF_EXITING point of no return.
This is purely a robustness check.
Link: http://lkml.kernel.org/r/20170224181957.19736-3-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrea Arcangeli [Fri, 10 Mar 2017 00:16:49 +0000 (16:16 -0800)]
userfaultfd: non-cooperative: rollback userfaultfd_exit
Patch series "userfaultfd non-cooperative further update for 4.11 merge
window".
Unfortunately I noticed one relevant bug in userfaultfd_exit while doing
more testing. I've been doing testing before and this was also tested
by kbuild bot and exercised by the selftest, but this bug never
reproduced before.
I dropped userfaultfd_exit as result. I dropped it because of
implementation difficulty in receiving signals in __mmput and because I
think -ENOSPC as result from the background UFFDIO_COPY should be enough
already.
Before I decided to remove userfaultfd_exit, I noticed userfaultfd_exit
wasn't exercised by the selftest and when I tried to exercise it, after
moving it to a more correct place in __mmput where it would make more
sense and where the vma list is stable, it resulted in the
event_wait_completion in D state. So then I added the second patch to
be sure even if we call userfaultfd_event_wait_completion too late
during task exit(), we won't risk to generate tasks in D state. The
same check exists in handle_userfault() for the same reason, except it
makes a difference there, while here is just a robustness check and it's
run under WARN_ON_ONCE.
While looking at the userfaultfd_event_wait_completion() function I
looked back at its callers too while at it and I think it's not ok to
stop executing dup_fctx on the fcs list because we relay on
userfaultfd_event_wait_completion to execute
userfaultfd_ctx_put(fctx->orig) which is paired against
userfaultfd_ctx_get(fctx->orig) in dup_userfault just before
list_add(fcs). This change only takes care of fctx->orig but this area
also needs further review looking for similar problems in fctx->new.
The only patch that is urgent is the first because it's an use after
free during a SMP race condition that affects all processes if
CONFIG_USERFAULTFD=y. Very hard to reproduce though and probably
impossible without SLUB poisoning enabled.
This patch (of 3):
I once reproduced this oops with the userfaultfd selftest, it's not
easily reproducible and it requires SLUB poisoning to reproduce.
general protection fault: 0000 [#1] SMP
Modules linked in:
CPU: 2 PID: 18421 Comm: userfaultfd Tainted: G ------------ T 3.10.0+ #15
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.10.1-0-g8891697-prebuilt.qemu-project.org 04/01/2014
task:
ffff8801f83b9440 ti:
ffff8801f833c000 task.ti:
ffff8801f833c000
RIP: 0010:[<
ffffffff81451299>] [<
ffffffff81451299>] userfaultfd_exit+0x29/0xa0
RSP: 0018:
ffff8801f833fe80 EFLAGS:
00010202
RAX:
ffff8801f833ffd8 RBX:
6b6b6b6b6b6b6b6b RCX:
ffff8801f83b9440
RDX:
0000000000000000 RSI:
0000000000000000 RDI:
ffff8800baf18600
RBP:
ffff8801f833fee8 R08:
0000000000000000 R09:
0000000000000001
R10:
0000000000000000 R11:
ffffffff8127ceb3 R12:
0000000000000000
R13:
ffff8800baf186b0 R14:
ffff8801f83b99f8 R15:
00007faed746c700
FS:
0000000000000000(0000) GS:
ffff88023fc80000(0000) knlGS:
0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0:
000000008005003b
CR2:
00007faf0966f028 CR3:
0000000001bc6000 CR4:
00000000000006e0
DR0:
0000000000000000 DR1:
0000000000000000 DR2:
0000000000000000
DR3:
0000000000000000 DR6:
00000000ffff0ff0 DR7:
0000000000000400
Call Trace:
do_exit+0x297/0xd10
SyS_exit+0x17/0x20
tracesys+0xdd/0xe2
Code: 00 00 66 66 66 66 90 55 48 89 e5 41 54 53 48 83 ec 58 48 8b 1f 48 85 db 75 11 eb 73 66 0f 1f 44 00 00 48 8b 5b 10 48 85 db 74 64 <4c> 8b a3 b8 00 00 00 4d 85 e4 74 eb 41 f6 84 24 2c 01 00 00 80
RIP [<
ffffffff81451299>] userfaultfd_exit+0x29/0xa0
RSP <
ffff8801f833fe80>
---[ end trace
9fecd6dcb442846a ]---
In the debugger I located the "mm" pointer in the stack and walking
mm->mmap->vm_next through the end shows the vma->vm_next list is fully
consistent and it is null terminated list as expected. So this has to
be an SMP race condition where userfaultfd_exit was running while the
vma list was being modified by another CPU.
When userfaultfd_exit() run one of the ->vm_next pointers pointed to
SLAB_POISON (RBX is the vma pointer and is 0x6b6b..).
The reason is that it's not running in __mmput but while there are still
other threads running and it's not holding the mmap_sem (it can't as it
has to wait the even to be received by the manager). So this is an use
after free that was happening for all processes.
One more implementation problem aside from the race condition:
userfaultfd_exit has really to check a flag in mm->flags before walking
the vma or it's going to slowdown the exit() path for regular tasks.
One more implementation problem: at that point signals can't be
delivered so it would also create a task in D state if the manager
doesn't read the event.
The major design issue: it overall looks superfluous as the manager can
check for -ENOSPC in the background transfer:
if (mmget_not_zero(ctx->mm)) {
[..]
} else {
return -ENOSPC;
}
It's safer to roll it back and re-introduce it later if at all.
[rppt@linux.vnet.ibm.com: documentation fixup after removal of UFFD_EVENT_EXIT]
Link: http://lkml.kernel.org/r/1488345437-4364-1-git-send-email-rppt@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/20170224181957.19736-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dan Williams [Fri, 10 Mar 2017 00:16:45 +0000 (16:16 -0800)]
x86, mm: unify exit paths in gup_pte_range()
All exit paths from gup_pte_range() require pte_unmap() of the original
pte page before returning. Refactor the code to have a single exit
point to do the unmap.
This mirrors the flow of the generic gup_pte_range() in mm/gup.c.
Link: http://lkml.kernel.org/r/148804251828.36605.14910389618497006945.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dan Williams [Fri, 10 Mar 2017 00:16:42 +0000 (16:16 -0800)]
x86, mm: fix gup_pte_range() vs DAX mappings
gup_pte_range() fails to check pte_allows_gup() before translating a DAX
pte entry, pte_devmap(), to a page. This allows writes to read-only
mappings, and bypasses the DAX cacheline dirty tracking due to missed
'mkwrite' faults. The gup_huge_pmd() path and the gup_huge_pud() path
correctly check pte_allows_gup() before checking for _devmap() entries.
Fixes:
3565fce3a659 ("mm, x86: get_user_pages() for dax mappings")
Link: http://lkml.kernel.org/r/148804251312.36605.12665024794196605053.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Dave Hansen <dave.hansen@linux.intel.com>
Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Xiong Zhou <xzhou@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Aneesh Kumar K.V [Fri, 10 Mar 2017 00:16:39 +0000 (16:16 -0800)]
power/mm: update pte_write and pte_wrprotect to handle savedwrite
We use pte_write() to check whethwer the pte entry is writable. This is
mostly used to later mark the pte read only if it is writable. The other
use of pte_write() is to check whether the pte_entry is writable so that
hardware page table entry can be marked accordingly. This is used in kvm
where we look at qemu page table entry and update hardware hash page table
for the guest with correct write enable bit.
With the above, for the first usage we should also check the savedwrite
bit so that we can correctly clear the savedwite bit. For the later, we
add a new variant __pte_write().
With this we can revert write_protect_page part of
595cd8f256d2 ("mm/ksm:
handle protnone saved writes when making page write protect"). But I left
it as it is as an example code for savedwrite check.
Fixes:
c137a2757b886 ("powerpc/mm/autonuma: switch ppc64 to its own implementation of saved write")
Link: http://lkml.kernel.org/r/1488203787-17849-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Aneesh Kumar K.V [Fri, 10 Mar 2017 00:16:36 +0000 (16:16 -0800)]
powerpc/mm: handle protnone ptes on fork
We need to mark pages of parent process read only on fork. Numa fault
pte needs a protnone ptes variant with saved write flag set. On fork we
need to make sure we remove the saved write bit. Instead of adding the
protnone check in the caller update ptep_set_wrprotect variants to clear
savedwrite bit.
Without this we see random segfaults in application on fork.
Fixes:
c137a2757b886 ("powerpc/mm/autonuma: switch ppc64 to its own implementation of saved write")
Link: http://lkml.kernel.org/r/1488203787-17849-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Masahiro Yamada [Fri, 10 Mar 2017 00:16:33 +0000 (16:16 -0800)]
scripts/spelling.txt: add "overide" pattern and fix typo instances
Fix typos and add the following to the scripts/spelling.txt:
overide||override
While we are here, fix the doubled "address" in the touched line
Documentation/devicetree/bindings/regulator/ti-abb-regulator.txt.
Also, fix the comment block style in the touched hunks in
drivers/media/dvb-frontends/drx39xyj/drx_driver.h.
Link: http://lkml.kernel.org/r/1481573103-11329-21-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Masahiro Yamada [Fri, 10 Mar 2017 00:16:31 +0000 (16:16 -0800)]
scripts/spelling.txt: add "disble(d)" pattern and fix typo instances
Fix typos and add the following to the scripts/spelling.txt:
disble||disable
disbled||disabled
I kept the TSL2563_INT_DISBLED in /drivers/iio/light/tsl2563.c
untouched. The macro is not referenced at all, but this commit is
touching only comment blocks just in case.
Link: http://lkml.kernel.org/r/1481573103-11329-20-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrea Arcangeli [Fri, 10 Mar 2017 00:16:28 +0000 (16:16 -0800)]
userfaultfd: shmem: __do_fault requires VM_FAULT_NOPAGE
__do_fault assumes vmf->page has been initialized and is valid if
VM_FAULT_NOPAGE is not returned by vma->vm_ops->fault(vma, vmf).
handle_userfault() in turn should return VM_FAULT_NOPAGE if it doesn't
return VM_FAULT_SIGBUS or VM_FAULT_RETRY (the other two possibilities).
This VM_FAULT_NOPAGE case is only invoked when signal are pending and it
didn't matter for anonymous memory before. It only started to matter
since shmem was introduced. hugetlbfs also takes a different path and
doesn't exercise __do_fault.
Link: http://lkml.kernel.org/r/20170228154201.GH5816@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Fri, 10 Mar 2017 00:30:37 +0000 (16:30 -0800)]
Merge tag 'pm-4.11-rc2' of git://git./linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These fix several issues in the intel_pstate driver and one issue in
the schedutil cpufreq governor, clean up that governor a bit and hook
up existing code for disabling cpufreq to a new kernel command line
option.
Specifics:
- Three fixes for intel_pstate problems related to the passive mode
(in which it acts as a regular cpufreq scaling driver), two for the
handling of global P-state limits and one for the handling of the
cpu_frequency tracepoint in that mode (Rafael Wysocki).
- Three fixes for the handling of P-state limits in intel_pstate in
the active mode (Rafael Wysocki).
- Introduction of a new cpufreq.off=1 kernel command line argument
that will disable cpufreq entirely if passed to the kernel and is
simply hooked up to the existing code used by Xen (Len Brown).
- Fix for the schedutil cpufreq governor to prevent it from using
stale raw frequency values in configurations with mutiple CPUs
sharing one policy object and a cleanup for it reducing its
overhead slightly (Viresh Kumar)"
* tag 'pm-4.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: intel_pstate: Do not reinit performance limits in ->setpolicy
cpufreq: intel_pstate: Fix intel_pstate_verify_policy()
cpufreq: intel_pstate: Fix global settings in active mode
cpufreq: Add the "cpufreq.off=1" cmdline option
cpufreq: schedutil: Pass sg_policy to get_next_freq()
cpufreq: schedutil: move cached_raw_freq to struct sugov_policy
cpufreq: intel_pstate: Avoid triggering cpu_frequency tracepoint unnecessarily
cpufreq: intel_pstate: Fix intel_cpufreq_verify_policy()
cpufreq: intel_pstate: Do not use performance_limits in passive mode
Linus Torvalds [Fri, 10 Mar 2017 00:02:04 +0000 (16:02 -0800)]
Merge tag 'pci-v4.11-fixes-2' of git://git./linux/kernel/git/helgaas/pci
Pull PCI fixes from Bjorn Helgaas:
"PCI fixes:
- fix NULL pointer dereference in Exynos driver
- fix NULL pointer dereference in ASPM with pre-1.1 PCIe devices
- blacklist QLogic ISP2722 to prevent panics while reading VPD"
* tag 'pci-v4.11-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
PCI/ASPM: Always set link->downstream to avoid NULL dereference on remove
PCI: Prevent VPD access for QLogic ISP2722
PCI: exynos: Initialize elbi_base even when using PHY framework
Linus Torvalds [Thu, 9 Mar 2017 23:53:25 +0000 (15:53 -0800)]
Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
"Sending this a bit sooner than I otherwise would have, as a fix in the
merge window had some unfortunate issues and side effects for some
folks.
This contains:
- Fixes from Jan for the bdi registration/unregistration. These have
been tested by the various parties reporting issues, and should be
solid at this point.
- Also from Jan, fix for axonram gendisk registration.
- A stable fix for zram from Johannes.
- A small series from Ming, fixing up some long standing issues with
blk-mq hardware queue kobject initialization and registration.
- A fix for sed opal from Jon, fixing a nonsensical range check and
some set-but-not-used variables.
- A fix from Neil for a long standing deadlock issue for stacking
device drivers. With this in place, dm/md don't have to work around
the issue anymore, and can be properly fixed up"
* 'for-linus' of git://git.kernel.dk/linux-block:
axonram: Fix gendisk handling
blk: improve order of bio handling in generic_make_request()
Revert "scsi, block: fix duplicate bdi name registration crashes"
block: Make del_gendisk() safer for disks without queues
bdi: Fix use-after-free in wb_congested_put()
block: Allow bdi re-registration
block/sed: Fix opal user range check and unused variables
zram: set physical queue limits to avoid array out of bounds accesses
blk-mq: free hctx->cpumask in release handler of hctx's kobject
blk-mq: make lifetime consistent between hctx and its kobject
blk-mq: make lifetime consitent between q/ctx and its kobject
blk-mq: initialize mq kobjects in blk_mq_init_allocated_queue()
Linus Torvalds [Thu, 9 Mar 2017 23:50:56 +0000 (15:50 -0800)]
Merge tag 'media/v4.11-2' of git://git./linux/kernel/git/mchehab/linux-media
Pull media fixes from Mauro Carvalho Chehab:
"Media regression fixes:
- serial_ir: fix a Kernel crash during boot on Kernel 4.11-rc1, due
to an IRQ code called too early
- other IR regression fixes at lirc and at the raw IR decoding
- a deadlock fix at the RC nuvoton driver
- fix another issue with DMA on stack at dw2102 driver
There's an extra patch there that change a driver interface for the
SoC VSP1 driver, with is shared between the DRM and V4L2 driver. The
patch itself is trivial, and was acked by David Arlie"
* tag 'media/v4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
[media] v4l: vsp1: Adapt vsp1_du_setup_lif() interface to use a structure
[media] dw2102: don't do DMA on stack
[media] rc: protocol is not set on register for raw IR devices
[media] rc: raw decoder for keymap protocol is not loaded on register
[media] rc: nuvoton: fix deadlock in nvt_write_wakeup_codes
[media] lirc: fix dead lock between open and wakeup_filter
[media] serial_ir: ensure we're ready to receive interrupts
Heiko Carstens [Mon, 6 Mar 2017 08:57:17 +0000 (09:57 +0100)]
s390: wire up statx system call
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>