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Quentin Monnet [Fri, 30 Jul 2021 21:54:29 +0000 (22:54 +0100)]
tools: bpftool: Slightly ease bash completion updates
Bash completion for bpftool gets two minor improvements in this patch.
Move the detection of attach types for "bpftool cgroup attach" outside
of the "case/esac" bloc, where we cannot reuse our variable holding the
list of supported attach types as a pattern list. After the change, we
have only one list of cgroup attach types to update when new types are
added, instead of the former two lists.
Also rename the variables holding lists of names for program types, map
types, and attach types, to make them more unique. This can make it
slightly easier to point people to the relevant variables to update, but
the main objective here is to help run a script to check that bash
completion is up-to-date with bpftool's source code.
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210730215435.7095-2-quentin@isovalent.com
Cong Wang [Fri, 23 Jul 2021 18:36:30 +0000 (11:36 -0700)]
unix_bpf: Fix a potential deadlock in unix_dgram_bpf_recvmsg()
As Eric noticed, __unix_dgram_recvmsg() may acquire u->iolock
too, so we have to release it before calling this function.
Fixes:
9825d866ce0d ("af_unix: Implement unix_dgram_bpf_recvmsg()")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Hengqi Chen [Fri, 30 Jul 2021 11:40:12 +0000 (19:40 +0800)]
libbpf: Add btf__load_vmlinux_btf/btf__load_module_btf
Add two new APIs: btf__load_vmlinux_btf and btf__load_module_btf.
btf__load_vmlinux_btf is just an alias to the existing API named
libbpf_find_kernel_btf, rename to be more precisely and consistent
with existing BTF APIs. btf__load_module_btf can be used to load
module BTF, add it for completeness. These two APIs are useful for
implementing tracing tools and introspection tools. This is part
of the effort towards libbpf 1.0 ([0]).
[0] Closes: https://github.com/libbpf/libbpf/issues/280
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210730114012.494408-1-hengqi.chen@gmail.com
Andrii Nakryiko [Fri, 30 Jul 2021 00:03:42 +0000 (17:03 -0700)]
Merge branch 'libbpf: rename btf__get_from_id() and btf__load() APIs, support split BTF'
Quentin Monnet says:
====================
As part of the effort to move towards a v1.0 for libbpf [0], this set
improves some confusing function names related to BTF loading from and to
the kernel:
- btf__load() becomes btf__load_into_kernel().
- btf__get_from_id becomes btf__load_from_kernel_by_id().
- A new version btf__load_from_kernel_by_id_split() extends the former to
add support for split BTF.
The last patch is a trivial change to bpftool to add support for dumping
split BTF objects by referencing them by their id (and not only by their
BTF path).
[0] https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#btfh-apis
v3:
- Use libbpf_err_ptr() in btf__load_from_kernel_by_id(), ERR_PTR() in
bpftool's get_map_kv_btf().
- Move the definition of btf__load_from_kernel_by_id() closer to the
btf__parse() group in btf.h (move the legacy function with it).
- Fix a bug on the return value in libbpf_find_prog_btf_id(), as a new
patch.
- Move the btf__free() fixes to their own patch.
- Add "Fixes:" tags to relevant patches.
v2:
- Remove deprecation marking of legacy functions (patch 4/6 from v1).
- Make btf__load_from_kernel_by_id{,_split}() return the btf struct, adjust
surrounding code and call btf__free() when missing.
- Add new functions to v0.5.0 API (and not v0.6.0).
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Quentin Monnet [Thu, 29 Jul 2021 16:20:28 +0000 (17:20 +0100)]
tools: bpftool: Support dumping split BTF by id
Split BTF objects are typically BTF objects for kernel modules, which
are incrementally built on top of kernel BTF instead of redefining all
kernel symbols they need. We can use bpftool with its -B command-line
option to dump split BTF objects. It works well when the handle provided
for the BTF object to dump is a "path" to the BTF object, typically
under /sys/kernel/btf, because bpftool internally calls
btf__parse_split() which can take a "base_btf" pointer and resolve the
BTF reconstruction (although in that case, the "-B" option is
unnecessary because bpftool performs autodetection).
However, it did not work so far when passing the BTF object through its
id, because bpftool would call btf__get_from_id() which did not provide
a way to pass a "base_btf" pointer.
In other words, the following works:
# bpftool btf dump file /sys/kernel/btf/i2c_smbus -B /sys/kernel/btf/vmlinux
But this was not possible:
# bpftool btf dump id 6 -B /sys/kernel/btf/vmlinux
The libbpf API has recently changed, and btf__get_from_id() has been
deprecated in favour of btf__load_from_kernel_by_id() and its version
with support for split BTF, btf__load_from_kernel_by_id_split(). Let's
update bpftool to make it able to dump the BTF object in the second case
as well.
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210729162028.29512-9-quentin@isovalent.com
Quentin Monnet [Thu, 29 Jul 2021 16:20:27 +0000 (17:20 +0100)]
libbpf: Add split BTF support for btf__load_from_kernel_by_id()
Add a new API function btf__load_from_kernel_by_id_split(), which takes
a pointer to a base BTF object in order to support split BTF objects
when retrieving BTF information from the kernel.
Reference: https://github.com/libbpf/libbpf/issues/314
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210729162028.29512-8-quentin@isovalent.com
Quentin Monnet [Thu, 29 Jul 2021 16:20:25 +0000 (17:20 +0100)]
tools: Replace btf__get_from_id() with btf__load_from_kernel_by_id()
Replace the calls to function btf__get_from_id(), which we plan to
deprecate before the library reaches v1.0, with calls to
btf__load_from_kernel_by_id() in tools/ (bpftool, perf, selftests).
Update the surrounding code accordingly (instead of passing a pointer to
the btf struct, get it as a return value from the function).
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210729162028.29512-6-quentin@isovalent.com
Quentin Monnet [Thu, 29 Jul 2021 16:20:24 +0000 (17:20 +0100)]
tools: Free BTF objects at various locations
Make sure to call btf__free() (and not simply free(), which does not
free all pointers stored in the struct) on pointers to struct btf
objects retrieved at various locations.
These were found while updating the calls to btf__get_from_id().
Fixes:
999d82cbc044 ("tools/bpf: enhance test_btf file testing to test func info")
Fixes:
254471e57a86 ("tools/bpf: bpftool: add support for func types")
Fixes:
7b612e291a5a ("perf tools: Synthesize PERF_RECORD_* for loaded BPF programs")
Fixes:
d56354dc4909 ("perf tools: Save bpf_prog_info and BTF of new BPF programs")
Fixes:
47c09d6a9f67 ("bpftool: Introduce "prog profile" command")
Fixes:
fa853c4b839e ("perf stat: Enable counting events for BPF programs")
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210729162028.29512-5-quentin@isovalent.com
Quentin Monnet [Thu, 29 Jul 2021 16:20:23 +0000 (17:20 +0100)]
libbpf: Rename btf__get_from_id() as btf__load_from_kernel_by_id()
Rename function btf__get_from_id() as btf__load_from_kernel_by_id() to
better indicate what the function does. Change the new function so that,
instead of requiring a pointer to the pointer to update and returning
with an error code, it takes a single argument (the id of the BTF
object) and returns the corresponding pointer. This is more in line with
the existing constructors.
The other tools calling the (soon-to-be) deprecated btf__get_from_id()
function will be updated in a future commit.
References:
- https://github.com/libbpf/libbpf/issues/278
- https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#btfh-apis
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210729162028.29512-4-quentin@isovalent.com
Quentin Monnet [Thu, 29 Jul 2021 16:20:22 +0000 (17:20 +0100)]
libbpf: Rename btf__load() as btf__load_into_kernel()
As part of the effort to move towards a v1.0 for libbpf, rename
btf__load() function, used to "upload" BTF information into the kernel,
as btf__load_into_kernel(). This new name better reflects what the
function does.
References:
- https://github.com/libbpf/libbpf/issues/278
- https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#btfh-apis
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210729162028.29512-3-quentin@isovalent.com
Quentin Monnet [Thu, 29 Jul 2021 16:20:21 +0000 (17:20 +0100)]
libbpf: Return non-null error on failures in libbpf_find_prog_btf_id()
Variable "err" is initialised to -EINVAL so that this error code is
returned when something goes wrong in libbpf_find_prog_btf_id().
However, a recent change in the function made use of the variable in
such a way that it is set to 0 if retrieving linear information on the
program is successful, and this 0 value remains if we error out on
failures at later stages.
Let's fix this by setting err to -EINVAL later in the function.
Fixes:
e9fc3ce99b34 ("libbpf: Streamline error reporting for high-level APIs")
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210729162028.29512-2-quentin@isovalent.com
Yonghong Song [Wed, 28 Jul 2021 18:30:25 +0000 (11:30 -0700)]
bpf: Emit better log message if bpf_iter ctx arg btf_id == 0
To avoid kernel build failure due to some missing .BTF-ids referenced
functions/types, the patch ([1]) tries to fill btf_id 0 for
these types.
In bpf verifier, for percpu variable and helper returning btf_id cases,
verifier already emitted proper warning with something like
verbose(env, "Helper has invalid btf_id in R%d\n", regno);
verbose(env, "invalid return type %d of func %s#%d\n",
fn->ret_type, func_id_name(func_id), func_id);
But this is not the case for bpf_iter context arguments.
I hacked resolve_btfids to encode btf_id 0 for struct task_struct.
With `./test_progs -n 7/5`, I got,
0: (79) r2 = *(u64 *)(r1 +0)
func 'bpf_iter_task' arg0 has btf_id 29739 type STRUCT 'bpf_iter_meta'
; struct seq_file *seq = ctx->meta->seq;
1: (79) r6 = *(u64 *)(r2 +0)
; struct task_struct *task = ctx->task;
2: (79) r7 = *(u64 *)(r1 +8)
; if (task == (void *)0) {
3: (55) if r7 != 0x0 goto pc+11
...
; BPF_SEQ_PRINTF(seq, "%8d %8d\n", task->tgid, task->pid);
26: (61) r1 = *(u32 *)(r7 +1372)
Type '(anon)' is not a struct
Basically, verifier will return btf_id 0 for task_struct.
Later on, when the code tries to access task->tgid, the
verifier correctly complains the type is '(anon)' and it is
not a struct. Users still need to backtrace to find out
what is going on.
Let us catch the invalid btf_id 0 earlier
and provide better message indicating btf_id is wrong.
The new error message looks like below:
R1 type=ctx expected=fp
; struct seq_file *seq = ctx->meta->seq;
0: (79) r2 = *(u64 *)(r1 +0)
func 'bpf_iter_task' arg0 has btf_id 29739 type STRUCT 'bpf_iter_meta'
; struct seq_file *seq = ctx->meta->seq;
1: (79) r6 = *(u64 *)(r2 +0)
; struct task_struct *task = ctx->task;
2: (79) r7 = *(u64 *)(r1 +8)
invalid btf_id for context argument offset 8
invalid bpf_context access off=8 size=8
[1] https://lore.kernel.org/bpf/
20210727132532.
2473636-1-hengqi.chen@gmail.com/
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210728183025.1461750-1-yhs@fb.com
Hengqi Chen [Tue, 27 Jul 2021 13:25:31 +0000 (21:25 +0800)]
tools/resolve_btfids: Emit warnings and patch zero id for missing symbols
Kernel functions referenced by .BTF_ids may be changed from global to static
and get inlined or get renamed/removed, and thus disappears from BTF.
This causes kernel build failure when resolve_btfids do id patch for symbols
in .BTF_ids in vmlinux. Update resolve_btfids to emit warning messages and
patch zero id for missing symbols instead of aborting kernel build process.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210727132532.2473636-2-hengqi.chen@gmail.com
Stanislav Fomichev [Tue, 27 Jul 2021 22:23:35 +0000 (15:23 -0700)]
bpf: Increase supported cgroup storage value size
Current max cgroup storage value size is 4k (PAGE_SIZE). The other local
storages accept up to 64k (BPF_LOCAL_STORAGE_MAX_VALUE_SIZE). Let's align
max cgroup value size with the other storages.
For percpu, the max is 32k (PCPU_MIN_UNIT_SIZE) because percpu
allocator is not happy about larger values.
netcnt test is extended to exercise those maximum values
(non-percpu max size is close to, but not real max).
v4:
* remove inner union (Andrii Nakryiko)
* keep net_cnt on the stack (Andrii Nakryiko)
v3:
* refine SIZEOF_BPF_LOCAL_STORAGE_ELEM comment (Yonghong Song)
* anonymous struct in percpu_net_cnt & net_cnt (Yonghong Song)
* reorder free (Yonghong Song)
v2:
* cap max_value_size instead of BUILD_BUG_ON (Martin KaFai Lau)
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210727222335.4029096-1-sdf@google.com
Martynas Pumputis [Mon, 26 Jul 2021 15:20:01 +0000 (17:20 +0200)]
libbpf: Fix race when pinning maps in parallel
When loading in parallel multiple programs which use the same to-be
pinned map, it is possible that two instances of the loader will call
bpf_object__create_maps() at the same time. If the map doesn't exist
when both instances call bpf_object__reuse_map(), then one of the
instances will fail with EEXIST when calling bpf_map__pin().
Fix the race by retrying reusing a map if bpf_map__pin() returns
EEXIST. The fix is similar to the one in iproute2:
e4c4685fd6e4 ("bpf:
Fix race condition with map pinning").
Before retrying the pinning, we don't do any special cleaning of an
internal map state. The closer code inspection revealed that it's not
required:
- bpf_object__create_map(): map->inner_map is destroyed after a
successful call, map->fd is closed if pinning fails.
- bpf_object__populate_internal_map(): created map elements is
destroyed upon close(map->fd).
- init_map_slots(): slots are freed after their initialization.
Signed-off-by: Martynas Pumputis <m@lambda.lt>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210726152001.34845-1-m@lambda.lt
Jason Wang [Tue, 27 Jul 2021 11:59:28 +0000 (19:59 +0800)]
libbpf: Fix comment typo
Remove the repeated word 'the' in line 48.
Signed-off-by: Jason Wang <wangborong@cdjrlc.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210727115928.74600-1-wangborong@cdjrlc.com
Juhee Kang [Tue, 27 Jul 2021 04:10:56 +0000 (04:10 +0000)]
samples: bpf: Add the omitted xdp samples to .gitignore
There are recently added xdp samples (xdp_redirect_map_multi and
xdpsock_ctrl_proc) which are not managed by .gitignore.
This commit adds these files to .gitignore.
Signed-off-by: Juhee Kang <claudiajkang@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210727041056.23455-2-claudiajkang@gmail.com
Juhee Kang [Tue, 27 Jul 2021 04:10:55 +0000 (04:10 +0000)]
samples: bpf: Fix tracex7 error raised on the missing argument
The current behavior of 'tracex7' doesn't consist with other bpf samples
tracex{1..6}. Other samples do not require any argument to run with, but
tracex7 should be run with btrfs device argument. (it should be executed
with test_override_return.sh)
Currently, tracex7 doesn't have any description about how to run this
program and raises an unexpected error. And this result might be
confusing since users might not have a hunch about how to run this
program.
// Current behavior
# ./tracex7
sh: 1: Syntax error: word unexpected (expecting ")")
// Fixed behavior
# ./tracex7
ERROR: Run with the btrfs device argument!
In order to fix this error, this commit adds logic to report a message
and exit when running this program with a missing argument.
Additionally in test_override_return.sh, there is a problem with
multiple directory(tmpmnt) creation. So in this commit adds a line with
removing the directory with every execution.
Signed-off-by: Juhee Kang <claudiajkang@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210727041056.23455-1-claudiajkang@gmail.com
Jussi Maki [Thu, 8 Jul 2021 02:17:27 +0000 (02:17 +0000)]
selftests/bpf: Use ping6 only if available in tc_redirect
In the tc_redirect test only use ping6 if it's available and
otherwise fall back to using "ping -6".
Signed-off-by: Jussi Maki <joamaki@gmail.com>
Andrii Nakryiko [Mon, 26 Jul 2021 19:11:23 +0000 (12:11 -0700)]
Merge branch 'libbpf: Move CO-RE logic into separate file.'
Alexei Starovoitov says:
====================
From: Alexei Starovoitov <ast@kernel.org>
Split CO-RE processing logic from libbpf into separate file
with an interface that doesn't dependend on libbpf internal details.
As the next step relo_core.c will be compiled with libbpf and with the kernel.
The _internal_ interface between libbpf/CO-RE and kernel/CO-RE will be:
int bpf_core_apply_relo_insn(const char *prog_name, struct bpf_insn *insn,
int insn_idx,
const struct bpf_core_relo *relo,
int relo_idx,
const struct btf *local_btf,
struct bpf_core_cand_list *cands);
where bpf_core_relo and bpf_core_cand_list are simple types
prepared by kernel and libbpf.
Though diff stat shows a lot of lines inserted/deleted they are moved lines.
Pls review with diff.colorMoved.
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Alexei Starovoitov [Wed, 21 Jul 2021 00:08:22 +0000 (17:08 -0700)]
libbpf: Split CO-RE logic into relo_core.c.
Move CO-RE logic into separate file.
The internal interface between libbpf and CO-RE is through
bpf_core_apply_relo_insn() function and few structs defined in relo_core.h.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210721000822.40958-5-alexei.starovoitov@gmail.com
Alexei Starovoitov [Wed, 21 Jul 2021 00:08:21 +0000 (17:08 -0700)]
libbpf: Move CO-RE types into relo_core.h.
In order to make a clean split of CO-RE logic move its types
into independent header file.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210721000822.40958-4-alexei.starovoitov@gmail.com
Alexei Starovoitov [Wed, 21 Jul 2021 00:08:20 +0000 (17:08 -0700)]
libbpf: Split bpf_core_apply_relo() into bpf_program independent helper.
bpf_core_apply_relo() doesn't need to know bpf_program internals
and hashmap details.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210721000822.40958-3-alexei.starovoitov@gmail.com
Alexei Starovoitov [Wed, 21 Jul 2021 00:08:19 +0000 (17:08 -0700)]
libbpf: Cleanup the layering between CORE and bpf_program.
CO-RE processing functions don't need to know 'struct bpf_program' details.
Cleanup the layering to eventually be able to move CO-RE logic into a separate file.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210721000822.40958-2-alexei.starovoitov@gmail.com
Johan Almbladh [Wed, 21 Jul 2021 10:38:22 +0000 (12:38 +0200)]
bpf/tests: Do not PASS tests without actually testing the result
Each test case can have a set of sub-tests, where each sub-test can
run the cBPF/eBPF test snippet with its own data_size and expected
result. Before, the end of the sub-test array was indicated by both
data_size and result being zero. However, most or all of the internal
eBPF tests has a data_size of zero already. When such a test also had
an expected value of zero, the test was never run but reported as
PASS anyway.
Now the test runner always runs the first sub-test, regardless of the
data_size and result values. The sub-test array zero-termination only
applies for any additional sub-tests.
There are other ways fix it of course, but this solution at least
removes the surprise of eBPF tests with a zero result always succeeding.
Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210721103822.3755111-1-johan.almbladh@anyfinetworks.com
Johan Almbladh [Wed, 21 Jul 2021 10:40:58 +0000 (12:40 +0200)]
bpf/tests: Fix copy-and-paste error in double word test
This test now operates on DW as stated instead of W, which was
already covered by another test.
Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210721104058.3755254-1-johan.almbladh@anyfinetworks.com
Evgeniy Litvinenko [Fri, 23 Jul 2021 22:36:45 +0000 (15:36 -0700)]
selftests/bpf: Document vmtest.sh dependencies
Add a list of vmtest script dependencies to make it easier for new
contributors to get going.
Signed-off-by: Evgeniy Litvinenko <evgeniyl@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210723223645.907802-1-evgeniyl@fb.com
Evgeniy Litvinenko [Fri, 23 Jul 2021 22:15:11 +0000 (15:15 -0700)]
libbpf: Add bpf_map__pin_path function
Add bpf_map__pin_path, so that the inconsistently named
bpf_map__get_pin_path can be deprecated later. This is part of the
effort towards libbpf v1.0: https://github.com/libbpf/libbpf/issues/307
Also, add a selftest for the new function.
Signed-off-by: Evgeniy Litvinenko <evgeniyl@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210723221511.803683-1-evgeniyl@fb.com
Andrii Nakryiko [Fri, 23 Jul 2021 23:42:27 +0000 (16:42 -0700)]
Merge branch 'bpf: Allow bpf tcp iter to do bpf_(get|set)sockopt'
Martin KaFai says:
====================
This set is to allow bpf tcp iter to call bpf_(get|set)sockopt.
With bpf-tcp-cc, new algo rollout happens more often. Instead of
restarting the applications to pick up the new tcp-cc, this set
allows the bpf tcp iter to call bpf_(get|set)sockopt(TCP_CONGESTION).
It is not limited to TCP_CONGESTION, the bpf tcp iter can call
bpf_(get|set)sockopt() with other options. The bpf tcp iter can read
into all the fields of a tcp_sock, so there is a lot of flexibility
to select the desired sk to do setsockopt(), e.g. it can test for
TCP_LISTEN only and leave the established connections untouched,
or check the addr/port, or check the current tcp-cc name, ...etc.
Patch 1-4 are some cleanup and prep work in the tcp and bpf seq_file.
Patch 5 is to have the tcp seq_file iterate on the
port+addr lhash2 instead of the port only listening_hash.
Patch 6 is to have the bpf tcp iter doing batching which
then allows lock_sock. lock_sock is needed for setsockopt.
Patch 7 allows the bpf tcp iter to call bpf_(get|set)sockopt.
v2:
- Use __GFP_NOWARN in patch 6
- Add bpf_getsockopt() in patch 7 to give a symmetrical user experience.
selftest in patch 8 is changed to also cover bpf_getsockopt().
- Remove CAP_NET_ADMIN check in patch 7. Tracing bpf prog has already
required CAP_SYS_ADMIN or CAP_PERFMON.
- Move some def macros to bpf_tracing_net.h in patch 8
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Martin KaFai Lau [Thu, 1 Jul 2021 20:06:25 +0000 (13:06 -0700)]
bpf: selftest: Test batching and bpf_(get|set)sockopt in bpf tcp iter
This patch adds tests for the batching and bpf_(get|set)sockopt in
bpf tcp iter.
It first creates:
a) 1 non SO_REUSEPORT listener in lhash2.
b) 256 passive and active fds connected to the listener in (a).
c) 256 SO_REUSEPORT listeners in one of the lhash2 bucket.
The test sets all listeners and connections to bpf_cubic before
running the bpf iter.
The bpf iter then calls setsockopt(TCP_CONGESTION) to switch
each listener and connection from bpf_cubic to bpf_dctcp.
The bpf iter has a random_retry mode such that it can return EAGAIN
to the usespace in the middle of a batch.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210701200625.1036874-1-kafai@fb.com
Martin KaFai Lau [Thu, 1 Jul 2021 20:06:19 +0000 (13:06 -0700)]
bpf: tcp: Support bpf_(get|set)sockopt in bpf tcp iter
This patch allows bpf tcp iter to call bpf_(get|set)sockopt.
To allow a specific bpf iter (tcp here) to call a set of helpers,
get_func_proto function pointer is added to bpf_iter_reg.
The bpf iter is a tracing prog which currently requires
CAP_PERFMON or CAP_SYS_ADMIN, so this patch does not
impose other capability checks for bpf_(get|set)sockopt.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210701200619.1036715-1-kafai@fb.com
Martin KaFai Lau [Thu, 1 Jul 2021 20:06:13 +0000 (13:06 -0700)]
bpf: tcp: Bpf iter batching and lock_sock
This patch does batching and lock_sock for the bpf tcp iter.
It does not affect the proc fs iteration.
With bpf-tcp-cc, new algo rollout happens more often. Instead of
restarting the application to pick up the new tcp-cc, the next patch
will allow bpf iter to do setsockopt(TCP_CONGESTION). This requires
locking the sock.
Also, unlike the proc iteration (cat /proc/net/tcp[6]), the bpf iter
can inspect all fields of a tcp_sock. It will be useful to have a
consistent view on some of the fields (e.g. the ones reported in
tcp_get_info() that also acquires the sock lock).
Double lock: locking the bucket first and then locking the sock could
lead to deadlock. This patch takes a batching approach similar to
inet_diag. While holding the bucket lock, it batch a number of sockets
into an array first and then unlock the bucket. Before doing show(),
it then calls lock_sock_fast().
In a machine with ~400k connections, the maximum number of
sk in a bucket of the established hashtable is 7. 0.02% of
the established connections fall into this bucket size.
For listen hash (port+addr lhash2), the bucket is usually very
small also except for the SO_REUSEPORT use case which the
userspace could have one SO_REUSEPORT socket per thread.
While batching is used, it can also minimize the chance of missing
sock in the setsockopt use case if the whole bucket is batched.
This patch will start with a batch array with INIT_BATCH_SZ (16)
which will be enough for the most common cases. bpf_iter_tcp_batch()
will try to realloc to a larger array to handle exception case (e.g.
the SO_REUSEPORT case in the lhash2).
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210701200613.1036157-1-kafai@fb.com
Martin KaFai Lau [Thu, 1 Jul 2021 20:06:06 +0000 (13:06 -0700)]
tcp: seq_file: Replace listening_hash with lhash2
This patch moves the tcp seq_file iteration on listeners
from the port only listening_hash to the port+addr lhash2.
When iterating from the bpf iter, the next patch will need to
lock the socket such that the bpf iter can call setsockopt (e.g. to
change the TCP_CONGESTION). To avoid locking the bucket and then locking
the sock, the bpf iter will first batch some sockets from the same bucket
and then unlock the bucket. If the bucket size is small (which
usually is), it is easier to batch the whole bucket such that it is less
likely to miss a setsockopt on a socket due to changes in the bucket.
However, the port only listening_hash could have many listeners
hashed to a bucket (e.g. many individual VIP(s):443 and also
multiple by the number of SO_REUSEPORT). We have seen bucket size in
tens of thousands range. Also, the chance of having changes
in some popular port buckets (e.g. 443) is also high.
The port+addr lhash2 was introduced to solve this large listener bucket
issue. Also, the listening_hash usage has already been replaced with
lhash2 in the fast path inet[6]_lookup_listener(). This patch follows
the same direction on moving to lhash2 and iterates the lhash2
instead of listening_hash.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210701200606.1035783-1-kafai@fb.com
Martin KaFai Lau [Thu, 1 Jul 2021 20:06:00 +0000 (13:06 -0700)]
tcp: seq_file: Add listening_get_first()
The current listening_get_next() is overloaded by passing
NULL to the 2nd arg, like listening_get_next(seq, NULL), to
mean get_first().
This patch moves some logic from the listening_get_next() into
a new function listening_get_first(). It will be equivalent
to the current established_get_first() and established_get_next()
setup. get_first() is to find a non empty bucket and return
the first sk. get_next() is to find the next sk of the current
bucket and then resorts to get_first() if the current bucket is
exhausted.
The next patch is to move the listener seq_file iteration from
listening_hash (port only) to lhash2 (port+addr).
Separating out listening_get_first() from listening_get_next()
here will make the following lhash2 changes cleaner and easier to
follow.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210701200600.1035353-1-kafai@fb.com
Martin KaFai Lau [Thu, 1 Jul 2021 20:05:54 +0000 (13:05 -0700)]
bpf: tcp: seq_file: Remove bpf_seq_afinfo from tcp_iter_state
A following patch will create a separate struct to store extra
bpf_iter state and it will embed the existing tcp_iter_state like this:
struct bpf_tcp_iter_state {
struct tcp_iter_state state;
/* More bpf_iter specific states here ... */
}
As a prep work, this patch removes the
"struct tcp_seq_afinfo *bpf_seq_afinfo" where its purpose is
to tell if it is iterating from bpf_iter instead of proc fs.
Currently, if "*bpf_seq_afinfo" is not NULL, it is iterating from
bpf_iter. The kernel should not filter by the addr family and
leave this filtering decision to the bpf prog.
Instead of adding a "*bpf_seq_afinfo" pointer, this patch uses the
"seq->op == &bpf_iter_tcp_seq_ops" test to tell if it is iterating
from the bpf iter.
The bpf_iter_(init|fini)_tcp() is left here to prepare for
the change of a following patch.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210701200554.1034982-1-kafai@fb.com
Martin KaFai Lau [Thu, 1 Jul 2021 20:05:48 +0000 (13:05 -0700)]
tcp: seq_file: Refactor net and family matching
This patch refactors the net and family matching into
two new helpers, seq_sk_match() and seq_file_family().
seq_file_family() is in the later part of the file to prepare
the change of a following patch.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210701200548.1034629-1-kafai@fb.com
Martin KaFai Lau [Thu, 1 Jul 2021 20:05:41 +0000 (13:05 -0700)]
tcp: seq_file: Avoid skipping sk during tcp_seek_last_pos
st->bucket stores the current bucket number.
st->offset stores the offset within this bucket that is the sk to be
seq_show(). Thus, st->offset only makes sense within the same
st->bucket.
These two variables are an optimization for the common no-lseek case.
When resuming the seq_file iteration (i.e. seq_start()),
tcp_seek_last_pos() tries to continue from the st->offset
at bucket st->bucket.
However, it is possible that the bucket pointed by st->bucket
has changed and st->offset may end up skipping the whole st->bucket
without finding a sk. In this case, tcp_seek_last_pos() currently
continues to satisfy the offset condition in the next (and incorrect)
bucket. Instead, regardless of the offset value, the first sk of the
next bucket should be returned. Thus, "bucket == st->bucket" check is
added to tcp_seek_last_pos().
The chance of hitting this is small and the issue is a decade old,
so targeting for the next tree.
Fixes:
a8b690f98baf ("tcp: Fix slowness in read /proc/net/tcp")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210701200541.1033917-1-kafai@fb.com
Jiri Olsa [Wed, 21 Jul 2021 21:58:10 +0000 (23:58 +0200)]
libbpf: Export bpf_program__attach_kprobe_opts function
Export bpf_program__attach_kprobe_opts as a public API.
Rename bpf_program_attach_kprobe_opts to bpf_kprobe_opts and turn it into OPTS
struct.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20210721215810.889975-4-jolsa@kernel.org
Jiri Olsa [Wed, 21 Jul 2021 21:58:09 +0000 (23:58 +0200)]
libbpf: Allow decimal offset for kprobes
Allow to specify decimal offset in SEC macro, like:
SEC("kprobe/bpf_fentry_test7+5")
Add selftest for that.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20210721215810.889975-3-jolsa@kernel.org
Jiri Olsa [Wed, 21 Jul 2021 21:58:08 +0000 (23:58 +0200)]
libbpf: Fix func leak in attach_kprobe
Add missing free() for func pointer in attach_kprobe function.
Fixes:
a2488b5f483f ("libbpf: Allow specification of "kprobe/function+offset"")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20210721215810.889975-2-jolsa@kernel.org
Martynas Pumputis [Wed, 21 Jul 2021 14:09:41 +0000 (16:09 +0200)]
selftests/bpf: Mute expected invalid map creation error msg
Previously, the newly introduced test case in test_map_in_map(), which
checks whether the inner map is destroyed after unsuccessful creation of
the outer map, logged the following harmless and expected error:
libbpf: map 'mim': failed to create: Invalid argument(-22) libbpf:
failed to load object './test_map_in_map_invalid.o'
To avoid any possible confusion, mute the logging during loading of the
prog.
Fixes:
08f71a1e39a1 ("selftests/bpf: Check inner map deletion")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Martynas Pumputis <m@lambda.lt>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210721140941.563175-1-m@lambda.lt
Colin Ian King [Wed, 21 Jul 2021 11:56:30 +0000 (12:56 +0100)]
bpf: Remove redundant intiialization of variable stype
The variable stype is being initialized with a value that is never
read, it is being updated later on. The assignment is redundant and
can be removed.
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210721115630.109279-1-colin.king@canonical.com
Arnd Bergmann [Wed, 21 Jul 2021 21:19:45 +0000 (23:19 +0200)]
bpf: Fix pointer cast warning
kp->addr is a pointer, so it cannot be cast directly to a 'u64'
when it gets interpreted as an integer value:
kernel/trace/bpf_trace.c: In function '____bpf_get_func_ip_kprobe':
kernel/trace/bpf_trace.c:968:21: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
968 | return kp ? (u64) kp->addr : 0;
Use the uintptr_t type instead.
Fixes:
9ffd9f3ff719 ("bpf: Add bpf_get_func_ip helper for kprobe programs")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210721212007.3876595-1-arnd@kernel.org
Andrii Nakryiko [Tue, 20 Jul 2021 20:49:25 +0000 (13:49 -0700)]
Merge branch 'libbpf: btf typed data dumping fixes (__int128 usage, error propagation)'
Alan Maguire says:
====================
This series aims to resolve further issues with the BTF typed data
dumping interfaces in libbpf.
Compilation failures with use of __int128 on 32-bit platforms were
reported [1]. As a result, the use of __int128 in libbpf typed data
dumping is replaced with __u64 usage for bitfield manipulations.
In the case of 128-bit integer values, they are simply split into
two 64-bit hex values for display (patch 1).
Tests are added for __int128 display in patch 2, using conditional
compilation to avoid problems with a lack of __int128 support.
Patch 3 resolves an issue Andrii noted about error propagation
when handling enum data display.
More followup work is required to ensure multi-dimensional char array
display works correctly.
[1] https://lore.kernel.org/bpf/
1626362126-27775-1-git-send-email-alan.maguire@oracle.com/T/#mc2cb023acfd6c3cd0b661e385787b76bb757430d
Changes since v1:
- added error handling for bitfield size > 64 bits by changing function
signature for bitfield retrieval to return an int error value and to set
bitfield value via a __u64 * argument (Andrii)
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Alan Maguire [Tue, 20 Jul 2021 08:49:53 +0000 (09:49 +0100)]
libbpf: Propagate errors when retrieving enum value for typed data display
When retrieving the enum value associated with typed data during
"is data zero?" checking in btf_dump_type_data_check_zero(), the
return value of btf_dump_get_enum_value() is not passed to the caller
if the function returns a non-zero (error) value. Currently, 0
is returned if the function returns an error. We should instead
propagate the error to the caller.
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1626770993-11073-4-git-send-email-alan.maguire@oracle.com
Alan Maguire [Tue, 20 Jul 2021 08:49:52 +0000 (09:49 +0100)]
selftests/bpf: Add __int128-specific tests for typed data dump
Add tests for __int128 display for platforms that support it.
__int128s are dumped as hex values.
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1626770993-11073-3-git-send-email-alan.maguire@oracle.com
Alan Maguire [Tue, 20 Jul 2021 08:49:51 +0000 (09:49 +0100)]
libbpf: Avoid use of __int128 in typed dump display
__int128 is not supported for some 32-bit platforms (arm and i386).
__int128 was used in carrying out computations on bitfields which
aid display, but the same calculations could be done with __u64
with the small effect of not supporting 128-bit bitfields.
With these changes, a big-endian issue with casting 128-bit integers
to 64-bit for enum bitfields is solved also, as we now use 64-bit
integers for bitfield calculations.
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1626770993-11073-2-git-send-email-alan.maguire@oracle.com
Vincent Li [Mon, 19 Jul 2021 22:30:22 +0000 (15:30 -0700)]
selftests, bpf: test_tc_tunnel.sh nc: Cannot use -p and -l
When run test_tc_tunnel.sh, it complains following error
ipip
encap 192.168.1.1 to 192.168.1.2, type ipip, mac none len 100
test basic connectivity
nc: cannot use -p and -l
nc man page has:
-l Listen for an incoming connection rather than initiating
a connection to a remote host.Cannot be used together with
any of the options -psxz. Additionally, any timeouts specified
with the -w option are ignored.
Correct nc in server_listen().
Signed-off-by: Vincent Li <vincent.mc.li@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210719223022.66681-1-vincent.mc.li@gmail.com
John Fastabend [Tue, 20 Jul 2021 18:48:32 +0000 (11:48 -0700)]
bpf, selftests: Fix test_maps now that sockmap supports UDP
UDP socket support was added recently so testing UDP insert failure is no
longer correct and causes test_maps failure. The fix is easy though, we
simply need to test that UDP is correctly added instead of blocked.
Fixes:
122e6c79efe1c ("sock_map: Update sock type checks for UDP")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210720184832.452430-1-john.fastabend@gmail.com
Martynas Pumputis [Mon, 19 Jul 2021 17:38:38 +0000 (19:38 +0200)]
selftests/bpf: Check inner map deletion
Add a test case to check whether an unsuccessful creation of an outer
map of a BTF-defined map-in-map destroys the inner map.
As bpf_object__create_map() is a static function, we cannot just call it
from the test case and then check whether a map accessible via
map->inner_map_fd has been closed. Instead, we iterate over all maps and
check whether the map "$MAP_NAME.inner" does not exist.
Signed-off-by: Martynas Pumputis <m@lambda.lt>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210719173838.423148-3-m@lambda.lt
Martynas Pumputis [Mon, 19 Jul 2021 17:38:37 +0000 (19:38 +0200)]
libbpf: Fix removal of inner map in bpf_object__create_map
If creating an outer map of a BTF-defined map-in-map fails (via
bpf_object__create_map()), then the previously created its inner map
won't be destroyed.
Fix this by ensuring that the destroy routines are not bypassed in the
case of a failure.
Fixes:
646f02ffdd49c ("libbpf: Add BTF-defined map-in-map support")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Martynas Pumputis <m@lambda.lt>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210719173838.423148-2-m@lambda.lt
Andrii Nakryiko [Sat, 17 Jul 2021 00:22:05 +0000 (17:22 -0700)]
Merge branch 'libbpf: BTF typed dump cleanups'
Alan Maguire says:
====================
Fix issues with libbpf BTF typed dump code. Patch 1 addresses handling
of unaligned data. Patch 2 fixes issues Andrii noticed when compiling
on ppc64le. Patch 3 simplifies typed dump by getting rid of allocation
of dump data structure which tracks dump state etc.
Changes since v1:
- Andrii suggested using a function instead of a macro for checking
alignment of data, and pointed out that we need to consider dump
ptr size versus native pointer size (patch 1)
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Alan Maguire [Fri, 16 Jul 2021 22:46:57 +0000 (23:46 +0100)]
libbpf: Btf typed dump does not need to allocate dump data
By using the stack for this small structure, we avoid the need
for freeing memory in error paths.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1626475617-25984-4-git-send-email-alan.maguire@oracle.com
Alan Maguire [Fri, 16 Jul 2021 22:46:56 +0000 (23:46 +0100)]
libbpf: Fix compilation errors on ppc64le for btf dump typed data
__s64 can be defined as either long or long long, depending on the
architecture. On ppc64le it's defined as long, giving this error:
In file included from btf_dump.c:22:
btf_dump.c: In function 'btf_dump_type_data_check_overflow':
libbpf_internal.h:111:22: error: format '%lld' expects argument of
type 'long long int', but argument 3 has type '__s64' {aka 'long int'}
[-Werror=format=]
111 | libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \
| ^~~~~~~~~~
libbpf_internal.h:114:27: note: in expansion of macro '__pr'
114 | #define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__)
| ^~~~
btf_dump.c:1992:3: note: in expansion of macro 'pr_warn'
1992 | pr_warn("unexpected size [%lld] for id [%u]\n",
| ^~~~~~~
btf_dump.c:1992:32: note: format string is defined here
1992 | pr_warn("unexpected size [%lld] for id [%u]\n",
| ~~~^
| |
| long long int
| %ld
Cast to size_t and use %zu instead.
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1626475617-25984-3-git-send-email-alan.maguire@oracle.com
Alan Maguire [Fri, 16 Jul 2021 22:46:55 +0000 (23:46 +0100)]
libbpf: Clarify/fix unaligned data issues for btf typed dump
If data is packed, data structures can store it outside of usual
boundaries. For example a 4-byte int can be stored on a unaligned
boundary in a case like this:
struct s {
char f1;
int f2;
} __attribute((packed));
...the int is stored at an offset of one byte. Some platforms have
problems dereferencing data that is not aligned with its size, and
code exists to handle most cases of this for BTF typed data display.
However pointer display was missed, and a simple function to test if
"ptr_is_aligned(data, data_sz)" would help clarify this code.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1626475617-25984-2-git-send-email-alan.maguire@oracle.com
Andrii Nakryiko [Fri, 16 Jul 2021 20:46:59 +0000 (13:46 -0700)]
Merge branch 'libbpf: BTF dumper support for typed data'
Alan Maguire says:
====================
Add a libbpf dumper function that supports dumping a representation
of data passed in using the BTF id associated with the data in a
manner similar to the bpf_snprintf_btf helper.
Default output format is identical to that dumped by bpf_snprintf_btf()
(bar using tabs instead of spaces for indentation, but the indent string
can be customized also); for example, a "struct sk_buff" representation
would look like this:
(struct sk_buff){
(union){
(struct){
.next = (struct sk_buff *)0xffffffffffffffff,
.prev = (struct sk_buff *)0xffffffffffffffff,
(union){
.dev = (struct net_device *)0xffffffffffffffff,
.dev_scratch = (long unsigned int)
18446744073709551615,
},
},
...
Patch 1 implements the dump functionality in a manner similar
to that in kernel/bpf/btf.c, but with a view to fitting into
libbpf more naturally. For example, rather than using flags,
boolean dump options are used to control output. In addition,
rather than combining checks for display (such as is this
field zero?) and actual display - as is done for the kernel
code - the code is organized to separate zero and overflow
checks from type display.
Patch 2 adds ASSERT_STRNEQ() for use in the following BTF dumper
tests.
Patch 3 consists of selftests that utilize a dump printf function
to snprintf the dump output to a string for comparison with
expected output. Tests deliberately mirror those in
snprintf_btf helper test to keep output consistent, but
also cover overflow handling, var/section display.
Changes since v5 [1]
- readjust dump options to avoid unnecessary padding (Andrii, patch 1).
- tidied up bitfield data checking/retrieval using Andrii's suggestions.
Removed code where we adjust data pointer prior to calling bitfield
functions as this adjustment is not needed, provided we use the type
size as the number of bytes to iterate over when retrieving the
full value we apply bit shifting operations to retrieve the bitfield
value. With these chances, the *_int_bits() functions were no longer needed
(Andrii, patch 1).
- coalesced the "is zero" checking for ints, floats and pointers
into btf_dump_base_type_check_zero(), using a memcmp() of the
size of the data. This can be derived from t->size for ints
and floats, and pointer size is retrieved from dump's ptr_sz
field (Andrii, patch 1).
- Added alignment-aware handling for int, enum, float retrieval.
Packed data structures can force ints, enums and floats to be
aligned on different boundaries; for example, the
struct p {
char f1;
int f2;
} __attribute__((packed));
...will have the int f2 field offset at byte 1, rather than at
byte 4 for an unpacked structure. The problem is directly
dereferencing that as an int is problematic on some platforms.
For ints and enums, we can reuse bitfield retrieval to get the
value for display, while for floats we use a local union of the
floating-point types and memcpy into it, ensuring we can then
dereference pointers into that union which will have safe alignment
(Andrii, patch 1).
- added comments to explain why we increment depth prior to displaying
opening parens, and decrement it prior to displaying closing parens
for structs, unions and arrays. The reason is that we don't want
to have a trailing newline when displaying a type. The logic that
handles this says "don't show a newline when the depth we're at is 0".
For this to work for opening parens then we need to bump depth before
showing opening parens + newline, and when we close out structure
we need to show closing parens after reducing depth so that we don't
append a newline to a top-level structure. So as a result we have
struct foo {\n
struct bar {\n
}\n
}
- silently truncate provided indent string with strncat() if > 31 bytes
(Andrii, patch 1).
- fixed ASSERT_STRNEQ() macro to show only n bytes of string
(Andrii, patch 2).
- fixed strncat() of type data string to avoid stack corruption
(Andrii, patch 3).
- removed early returns from dump type tests (Andrii, patch 3).
- have tests explicitly specify prefix (enum, struct, union)
(Andrii, patch 3).
- switch from CHECK() to ASSERT_* where possible (Andrii, patch 3).
Changes since v4 [2]
- Andrii kindly provided code to unify emitting a prepended cast
(for example "(int)") with existing code, and this had the nice
benefit of adding array indices in type specifications (Andrii,
patches 1, 3)
- Fixed indent_str option to make it a const char *, stored in a
fixed-length buffer internally (Andrii, patch 1)
- Reworked bit shift logic to minimize endian-specific interactions,
and use same macros as found elsewhere in libbpf to determine endianness
(Andrii, patch 1)
- Fixed type emitting to ensure that a trailing '\n' is not displayed;
newlines are added during struct/array display, but for a single type
the last character is no longer a newline (Andrii, patches 1, 3)
- Added support for ASSERT_STRNEQ() macro (Andrii, patch 2)
- Split tests into subtests for int, char, enum etc rather than one
"dump type data" subtest (Andrii, patch 3)
- Made better use of ASSERT* macros (Andrii, patch 3)
- Got rid of some other TEST_* macros that were unneeded (Andrii, patch 3)
- Switched to using "struct fs_context" to verify enum bitfield values
(Andrii, patch 3)
Changes since v3 [3]
- Retained separation of emitting of type name cast prefixing
type values from existing functionality such as btf_dump_emit_type_chain()
since initial code-shared version had so many exceptions it became
hard to read. For example, we don't emit a type name if the type
to be displayed is an array member, we also always emit "forward"
definitions for structs/unions that aren't really forward definitions
(we just want a "struct foo" output for "(struct foo){.bar = ...".
We also always ignore modifiers const/volatile/restrict as they
clutter output when emitting large types.
- Added configurable 4-char indent string option; defaults to tab
(Andrii)
- Added support for BTF_KIND_FLOAT and associated tests (Andrii)
- Added support for BTF_KIND_FUNC_PROTO function pointers to
improve output of "ops" structures; for example:
(struct file_operations){
.owner = (struct module *)0xffffffffffffffff,
.llseek = (loff_t(*)(struct file *, loff_t, int))0xffffffffffffffff,
...
Added associated test also (Andrii)
- Added handling for enum bitfields and associated test (Andrii)
- Allocation of "struct btf_dump_data" done on-demand (Andrii)
- Removed ".field = " output from function emitting type name and
into caller (Andrii)
- Removed BTF_INT_OFFSET() support (Andrii)
- Use libbpf_err() to set errno for error cases (Andrii)
- btf_dump_dump_type_data() returns size written, which is used
when returning successfully from btf_dump__dump_type_data()
(Andrii)
Changes since v2 [4]
- Renamed function to btf_dump__dump_type_data, reorganized
arguments such that opts are last (Andrii)
- Modified code to separate questions about display such
as have we overflowed?/is this field zero? from actual
display of typed data, such that we ask those questions
separately from the code that actually displays typed data
(Andrii)
- Reworked code to handle overflow - where we do not provide
enough data for the type we wish to display - by returning
-E2BIG and attempting to present as much data as possible.
Such a mode of operation allows for tracers which retrieve
partial data (such as first 1024 bytes of a
"struct task_struct" say), and want to display that partial
data, while also knowing that it is not the full type.
Such tracers can then denote this (perhaps via "..." or
similar).
- Explored reusing existing type emit functions, such as
passing in a type id stack with a single type id to
btf_dump_emit_type_chain() to support the display of
typed data where a "cast" is prepended to the data to
denote its type; "(int)1", "(struct foo){", etc.
However the task of emitting a
".field_name = (typecast)" did not match well with model
of walking the stack to display innermost types first
and made the resultant code harder to read. Added a
dedicated btf_dump_emit_type_name() function instead which
is only ~70 lines (Andrii)
- Various cleanups around bitfield macros, unneeded member
iteration macros, avoiding compiler complaints when
displaying int da ta by casting to long long, etc (Andrii)
- Use DECLARE_LIBBPF_OPTS() in defining opts for tests (Andrii)
- Added more type tests, overflow tests, var tests and
section tests.
Changes since RFC [5]
- The initial approach explored was to share the kernel code
with libbpf using #defines to paper over the different needs;
however it makes more sense to try and fit in with libbpf
code style for maintenance. A comment in the code points at
the implementation in kernel/bpf/btf.c and notes that any
issues found in it should be fixed there or vice versa;
mirroring the tests should help with this also
(Andrii)
[1] https://lore.kernel.org/bpf/
1624092968-5598-1-git-send-email-alan.maguire@oracle.com/
[2] https://lore.kernel.org/bpf/CAEf4BzYtbnphCkhz0epMKE4zWfvSOiMpu+-SXp9hadsrRApuZw@mail.gmail.com/T/
[3] https://lore.kernel.org/bpf/
1622131170-8260-1-git-send-email-alan.maguire@oracle.com/
[4] https://lore.kernel.org/bpf/
1610921764-7526-1-git-send-email-alan.maguire@oracle.com/
[5] https://lore.kernel.org/bpf/
1610386373-24162-1-git-send-email-alan.maguire@oracle.com/
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Alan Maguire [Thu, 15 Jul 2021 15:15:26 +0000 (16:15 +0100)]
selftests/bpf: Add dump type data tests to btf dump tests
Test various type data dumping operations by comparing expected
format with the dumped string; an snprintf-style printf function
is used to record the string dumped. Also verify overflow handling
where the data passed does not cover the full size of a type,
such as would occur if a tracer has a portion of the 8k
"struct task_struct".
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1626362126-27775-4-git-send-email-alan.maguire@oracle.com
Alan Maguire [Thu, 15 Jul 2021 15:15:25 +0000 (16:15 +0100)]
selftests/bpf: Add ASSERT_STRNEQ() variant for test_progs
It will support strncmp()-style string comparisons.
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1626362126-27775-3-git-send-email-alan.maguire@oracle.com
Alan Maguire [Thu, 15 Jul 2021 15:15:24 +0000 (16:15 +0100)]
libbpf: BTF dumper support for typed data
Add a BTF dumper for typed data, so that the user can dump a typed
version of the data provided.
The API is
int btf_dump__dump_type_data(struct btf_dump *d, __u32 id,
void *data, size_t data_sz,
const struct btf_dump_type_data_opts *opts);
...where the id is the BTF id of the data pointed to by the "void *"
argument; for example the BTF id of "struct sk_buff" for a
"struct skb *" data pointer. Options supported are
- a starting indent level (indent_lvl)
- a user-specified indent string which will be printed once per
indent level; if NULL, tab is chosen but any string <= 32 chars
can be provided.
- a set of boolean options to control dump display, similar to those
used for BPF helper bpf_snprintf_btf(). Options are
- compact : omit newlines and other indentation
- skip_names: omit member names
- emit_zeroes: show zero-value members
Default output format is identical to that dumped by bpf_snprintf_btf(),
for example a "struct sk_buff" representation would look like this:
struct sk_buff){
(union){
(struct){
.next = (struct sk_buff *)0xffffffffffffffff,
.prev = (struct sk_buff *)0xffffffffffffffff,
(union){
.dev = (struct net_device *)0xffffffffffffffff,
.dev_scratch = (long unsigned int)
18446744073709551615,
},
},
...
If the data structure is larger than the *data_sz*
number of bytes that are available in *data*, as much
of the data as possible will be dumped and -E2BIG will
be returned. This is useful as tracers will sometimes
not be able to capture all of the data associated with
a type; for example a "struct task_struct" is ~16k.
Being able to specify that only a subset is available is
important for such cases. On success, the amount of data
dumped is returned.
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1626362126-27775-2-git-send-email-alan.maguire@oracle.com
Andrii Nakryiko [Fri, 16 Jul 2021 19:45:57 +0000 (12:45 -0700)]
Merge branch 'Add btf_custom_path in bpf_obj_open_opts'
Shuyi Cheng says:
====================
This patch set adds the ability to point to a custom BTF for the
purposes of BPF CO-RE relocations. This is useful for using BPF CO-RE
on old kernels that don't yet natively support kernel (vmlinux) BTF
and thus libbpf needs application's help in locating kernel BTF
generated separately from the kernel itself. This was already possible
to do through bpf_object__load's attribute struct, but that makes it
inconvenient to use with BPF skeleton, which only allows to specify
bpf_object_open_opts during the open step. Thus, add the ability to
override vmlinux BTF at open time.
Patch #1 adds libbpf changes.
Patch #2 fixes pre-existing memory leak detected during the code review.
Patch #3 switches existing selftests to using open_opts for custom BTF.
Changelog:
----------
v3: https://lore.kernel.org/bpf/CAEf4BzY2cdT44bfbMus=gei27ViqGE1BtGo6XrErSsOCnqtVJg@mail.gmail.com/T/#m877eed1d4cf0a1d3352d3f3d6c5ff158be45c542
v3->v4:
- Follow Andrii's suggestion to modify cover letter description.
- Delete function bpf_object__load_override_btf.
- Follow Dan's suggestion to add fixes tag and modify commit msg to patch #2.
- Add pathch #3 to switch existing selftests to using open_opts.
v2: https://lore.kernel.org/bpf/CAEf4Bza_ua+tjxdhyy4nZ8Boeo+scipWmr_1xM1pC6N5wyuhAA@mail.gmail.com/T/#mf9cf86ae0ffa96180ac29e4fd12697eb70eccd0f
v2->v3:
- Load the BTF specified by btf_custom_path to btf_vmlinux_override
instead of btf_bmlinux.
- Fix the memory leak that may be introduced by the second version
of the patch.
- Add a new patch to fix the possible memory leak caused by
obj->kconfig.
v1: https://lore.kernel.org/bpf/CAEf4BzaGjEC4t1OefDo11pj2-HfNy0BLhs_G2UREjRNTmb2u=A@mail.gmail.com/t/#m4d9f7c6761fbd2b436b5dfe491cd864b70225804
v1->v2:
- Change custom_btf_path to btf_custom_path.
- If the length of btf_custom_path of bpf_obj_open_opts is too long,
return ERR_PTR(-ENAMETOOLONG).
- Add `custom BTF is in addition to vmlinux BTF` with btf_custom_path field.
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Shuyi Cheng [Tue, 13 Jul 2021 12:42:39 +0000 (20:42 +0800)]
selftests/bpf: Switch existing selftests to using open_opts for custom BTF
This patch mainly replaces the bpf_object_load_attr of
the core_autosize.c and core_reloc.c files with bpf_object_open_opts.
Signed-off-by: Shuyi Cheng <chengshuyi@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1626180159-112996-4-git-send-email-chengshuyi@linux.alibaba.com
Shuyi Cheng [Tue, 13 Jul 2021 12:42:38 +0000 (20:42 +0800)]
libbpf: Fix the possible memory leak on error
If the strdup() fails then we need to call bpf_object__close(obj) to
avoid a resource leak.
Fixes:
166750bc1dd2 ("libbpf: Support libbpf-provided extern variables")
Signed-off-by: Shuyi Cheng <chengshuyi@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1626180159-112996-3-git-send-email-chengshuyi@linux.alibaba.com
Shuyi Cheng [Tue, 13 Jul 2021 12:42:37 +0000 (20:42 +0800)]
libbpf: Introduce 'btf_custom_path' to 'bpf_obj_open_opts'
btf_custom_path allows developers to load custom BTF which libbpf will
subsequently use for CO-RE relocation instead of vmlinux BTF.
Having btf_custom_path in bpf_object_open_opts one can directly use the
skeleton's <objname>_bpf__open_opts() API to pass in the btf_custom_path
parameter, as opposed to using bpf_object__load_xattr() which is slated to be
deprecated ([0]).
This work continues previous work started by another developer ([1]).
[0] https://lore.kernel.org/bpf/CAEf4BzbJZLjNoiK8_VfeVg_Vrg=9iYFv+po-38SMe=UzwDKJ=Q@mail.gmail.com/#t
[1] https://yhbt.net/lore/all/CAEf4Bzbgw49w2PtowsrzKQNcxD4fZRE6AKByX-5-dMo-+oWHHA@mail.gmail.com/
Signed-off-by: Shuyi Cheng <chengshuyi@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1626180159-112996-2-git-send-email-chengshuyi@linux.alibaba.com
Roy, UjjaL [Fri, 16 Jul 2021 20:04:41 +0000 (22:04 +0200)]
bpf, doc: Add heading and example for extensions in cbpf
Add new heading for extensions to make it more readable. Also, add one
more example of filtering interface index for better understanding.
Signed-off-by: Roy, UjjaL <royujjal@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/CAADnVQJ=DoRDcVkaXmY3EmNdLoO7gq1mkJOn5G=00wKH8qUtZQ@mail.gmail.com
Andrii Nakryiko [Mon, 12 Jul 2021 23:06:15 +0000 (16:06 -0700)]
bpf: Add ambient BPF runtime context stored in current
b910eaaaa4b8 ("bpf: Fix NULL pointer dereference in bpf_get_local_storage()
helper") fixed the problem with cgroup-local storage use in BPF by
pre-allocating per-CPU array of 8 cgroup storage pointers to accommodate
possible BPF program preemptions and nested executions.
While this seems to work good in practice, it introduces new and unnecessary
failure mode in which not all BPF programs might be executed if we fail to
find an unused slot for cgroup storage, however unlikely it is. It might also
not be so unlikely when/if we allow sleepable cgroup BPF programs in the
future.
Further, the way that cgroup storage is implemented as ambiently-available
property during entire BPF program execution is a convenient way to pass extra
information to BPF program and helpers without requiring user code to pass
around extra arguments explicitly. So it would be good to have a generic
solution that can allow implementing this without arbitrary restrictions.
Ideally, such solution would work for both preemptable and sleepable BPF
programs in exactly the same way.
This patch introduces such solution, bpf_run_ctx. It adds one pointer field
(bpf_ctx) to task_struct. This field is maintained by BPF_PROG_RUN family of
macros in such a way that it always stays valid throughout BPF program
execution. BPF program preemption is handled by remembering previous
current->bpf_ctx value locally while executing nested BPF program and
restoring old value after nested BPF program finishes. This is handled by two
helper functions, bpf_set_run_ctx() and bpf_reset_run_ctx(), which are
supposed to be used before and after BPF program runs, respectively.
Restoring old value of the pointer handles preemption, while bpf_run_ctx
pointer being a property of current task_struct naturally solves this problem
for sleepable BPF programs by "following" BPF program execution as it is
scheduled in and out of CPU. It would even allow CPU migration of BPF
programs, even though it's not currently allowed by BPF infra.
This patch cleans up cgroup local storage handling as a first application. The
design itself is generic, though, with bpf_run_ctx being an empty struct that
is supposed to be embedded into a specific struct for a given BPF program type
(bpf_cg_run_ctx in this case). Follow up patches are planned that will expand
this mechanism for other uses within tracing BPF programs.
To verify that this change doesn't revert the fix to the original cgroup
storage issue, I ran the same repro as in the original report ([0]) and didn't
get any problems. Replacing bpf_reset_run_ctx(old_run_ctx) with
bpf_reset_run_ctx(NULL) triggers the issue pretty quickly (so repro does work).
[0] https://lore.kernel.org/bpf/YEEvBUiJl2pJkxTd@krava/
Fixes:
b910eaaaa4b8 ("bpf: Fix NULL pointer dereference in bpf_get_local_storage() helper")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210712230615.3525979-1-andrii@kernel.org
Peilin Ye [Fri, 16 Jul 2021 01:52:45 +0000 (18:52 -0700)]
netdevsim: Add multi-queue support
Currently netdevsim only supports a single queue per port, which is
insufficient for testing multi-queue TC schedulers e.g. sch_mq. Extend
the current sysfs interface so that users can create ports with multiple
queues:
$ echo "[ID] [PORT_COUNT] [NUM_QUEUES]" > /sys/bus/netdevsim/new_device
As an example, echoing "2 4 8" creates 4 ports, with 8 queues per port.
Note, this is compatible with the current interface, with default number
of queues set to 1. For example, echoing "2 4" creates 4 ports with 1
queue per port; echoing "2" simply creates 1 port with 1 queue.
Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Mark Gray [Thu, 15 Jul 2021 12:27:54 +0000 (08:27 -0400)]
openvswitch: Introduce per-cpu upcall dispatch
The Open vSwitch kernel module uses the upcall mechanism to send
packets from kernel space to user space when it misses in the kernel
space flow table. The upcall sends packets via a Netlink socket.
Currently, a Netlink socket is created for every vport. In this way,
there is a 1:1 mapping between a vport and a Netlink socket.
When a packet is received by a vport, if it needs to be sent to
user space, it is sent via the corresponding Netlink socket.
This mechanism, with various iterations of the corresponding user
space code, has seen some limitations and issues:
* On systems with a large number of vports, there is a correspondingly
large number of Netlink sockets which can limit scaling.
(https://bugzilla.redhat.com/show_bug.cgi?id=
1526306)
* Packet reordering on upcalls.
(https://bugzilla.redhat.com/show_bug.cgi?id=
1844576)
* A thundering herd issue.
(https://bugzilla.redhat.com/show_bug.cgi?id=
1834444)
This patch introduces an alternative, feature-negotiated, upcall
mode using a per-cpu dispatch rather than a per-vport dispatch.
In this mode, the Netlink socket to be used for the upcall is
selected based on the CPU of the thread that is executing the upcall.
In this way, it resolves the issues above as:
a) The number of Netlink sockets scales with the number of CPUs
rather than the number of vports.
b) Ordering per-flow is maintained as packets are distributed to
CPUs based on mechanisms such as RSS and flows are distributed
to a single user space thread.
c) Packets from a flow can only wake up one user space thread.
The corresponding user space code can be found at:
https://mail.openvswitch.org/pipermail/ovs-dev/2021-July/385139.html
Bugzilla: https://bugzilla.redhat.com/
1844576
Signed-off-by: Mark Gray <mark.d.gray@redhat.com>
Acked-by: Flavio Leitner <fbl@sysclose.org>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Bill Wendling [Wed, 14 Jul 2021 09:17:46 +0000 (02:17 -0700)]
bnx2x: remove unused variable 'cur_data_offset'
Fix the clang build warning:
drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.c:1862:13: error: variable 'cur_data_offset' set but not used [-Werror,-Wunused-but-set-variable]
dma_addr_t cur_data_offset;
Signed-off-by: Bill Wendling <morbo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Christophe JAILLET [Wed, 14 Jul 2021 08:32:33 +0000 (10:32 +0200)]
net: switchdev: Simplify 'mlxsw_sp_mc_write_mdb_entry()'
Use 'bitmap_alloc()/bitmap_free()' instead of hand-writing it.
This makes the code less verbose.
Also, use 'bitmap_alloc()' instead of 'bitmap_zalloc()' because the bitmap
is fully overridden by a 'bitmap_copy()' call just after its allocation.
While at it, remove an extra and unneeded space.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Yajun Deng [Thu, 15 Jul 2021 12:24:24 +0000 (20:24 +0800)]
net/sched: Remove unnecessary if statement
It has been deal with the 'if (err' statement in rtnetlink_send()
and rtnl_unicast(). so remove unnecessary if statement.
v2: use the raw name rtnetlink_send().
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>
Yajun Deng [Thu, 15 Jul 2021 12:12:57 +0000 (20:12 +0800)]
rtnetlink: use nlmsg_notify() in rtnetlink_send()
The netlink_{broadcast, unicast} don't deal with 'if (err > 0' statement
but nlmsg_{multicast, unicast} do. The nlmsg_notify() contains them.
so use nlmsg_notify() instead. so that the caller wouldn't deal with
'if (err > 0' statement.
v2: use nlmsg_notify() will do well.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>
Haiyue Wang [Wed, 14 Jul 2021 07:34:59 +0000 (15:34 +0800)]
gve: fix the wrong AdminQ buffer overflow check
The 'tail' pointer is also free-running count, so it needs to be masked
as 'adminq_prod_cnt' does, to become an index value of AdminQ buffer.
Fixes:
5cdad90de62c ("gve: Batch AQ commands for creating and destroying queues.")
Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
David S. Miller [Fri, 16 Jul 2021 05:40:10 +0000 (22:40 -0700)]
Merge git://git./linux/kernel/git/bpf/bpf-next
Alexei Starovoitov says:
====================
pull-request: bpf-next 2021-07-15
The following pull-request contains BPF updates for your *net-next* tree.
We've added 45 non-merge commits during the last 15 day(s) which contain
a total of 52 files changed, 3122 insertions(+), 384 deletions(-).
The main changes are:
1) Introduce bpf timers, from Alexei.
2) Add sockmap support for unix datagram socket, from Cong.
3) Fix potential memleak and UAF in the verifier, from He.
4) Add bpf_get_func_ip helper, from Jiri.
5) Improvements to generic XDP mode, from Kumar.
6) Support for passing xdp_md to XDP programs in bpf_prog_run, from Zvi.
===================
Signed-off-by: David S. Miller <davem@davemloft.net>
Alexei Starovoitov [Fri, 16 Jul 2021 01:17:51 +0000 (18:17 -0700)]
Merge branch 'sockmap: add sockmap support for unix datagram socket'
Cong Wang says:
====================
From: Cong Wang <cong.wang@bytedance.com>
This is the last patchset of the original large patchset. In the
previous patchset, a new BPF sockmap program BPF_SK_SKB_VERDICT
was introduced and UDP began to support it too. In this patchset,
we add BPF_SK_SKB_VERDICT support to Unix datagram socket, so that
we can finally splice Unix datagram socket and UDP socket. Please
check each patch description for more details.
To see the big picture, the previous patchsets are available here:
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit/?id=
1e0ab70778bd86a90de438cc5e1535c115a7c396
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit/?id=
89d69c5d0fbcabd8656459bc8b1a476d6f1efee4
and this patchset is available here:
https://github.com/congwang/linux/tree/sockmap3
Acked-by: John Fastabend <john.fastabend@gmail.com>
---
v5: lift socket state check for dgram
remove ->unhash() case
add retries for EAGAIN in all test cases
remove an unused parameter of __unix_dgram_recvmsg()
rebase on the latest bpf-next
v4: fix af_unix disconnect case
add unix_unhash()
split out two small patches
reduce u->iolock critical section
remove an unused parameter of __unix_dgram_recvmsg()
v3: fix Kconfig dependency
make unix_read_sock() static
fix a UAF in unix_release()
add a missing header unix_bpf.c
v2: separate out from the original large patchset
rebase to the latest bpf-next
clean up unix_read_sock()
export sock_map_close()
factor out some helpers in selftests for code reuse
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cong Wang [Sun, 4 Jul 2021 19:02:52 +0000 (12:02 -0700)]
selftests/bpf: Add test cases for redirection between udp and unix
Add two test cases to ensure redirection between udp and unix
work bidirectionally.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210704190252.11866-12-xiyou.wangcong@gmail.com
Cong Wang [Sun, 4 Jul 2021 19:02:51 +0000 (12:02 -0700)]
selftests/bpf: Add a test case for unix sockmap
Add a test case to ensure redirection between two AF_UNIX
datagram sockets work.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210704190252.11866-11-xiyou.wangcong@gmail.com
Cong Wang [Sun, 4 Jul 2021 19:02:50 +0000 (12:02 -0700)]
selftests/bpf: Factor out add_to_sockmap()
Factor out a common helper add_to_sockmap() which adds two
sockets into a sockmap.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210704190252.11866-10-xiyou.wangcong@gmail.com
Cong Wang [Sun, 4 Jul 2021 19:02:49 +0000 (12:02 -0700)]
selftests/bpf: Factor out udp_socketpair()
Factor out a common helper udp_socketpair() which creates
a pair of connected UDP sockets.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210704190252.11866-9-xiyou.wangcong@gmail.com
Cong Wang [Sun, 4 Jul 2021 19:02:48 +0000 (12:02 -0700)]
af_unix: Implement unix_dgram_bpf_recvmsg()
We have to implement unix_dgram_bpf_recvmsg() to replace the
original ->recvmsg() to retrieve skmsg from ingress_msg.
AF_UNIX is again special here because the lack of
sk_prot->recvmsg(). I simply add a special case inside
unix_dgram_recvmsg() to call sk->sk_prot->recvmsg() directly.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210704190252.11866-8-xiyou.wangcong@gmail.com
Cong Wang [Sun, 4 Jul 2021 19:02:47 +0000 (12:02 -0700)]
af_unix: Implement ->psock_update_sk_prot()
Now we can implement unix_bpf_update_proto() to update
sk_prot, especially prot->close().
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210704190252.11866-7-xiyou.wangcong@gmail.com
Cong Wang [Sun, 4 Jul 2021 19:02:46 +0000 (12:02 -0700)]
af_unix: Add a dummy ->close() for sockmap
Unlike af_inet, unix_proto is very different, it does not even
have a ->close(). We have to add a dummy implementation to
satisfy sockmap. Normally it is just a nop, it is introduced only
for sockmap to replace it.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210704190252.11866-6-xiyou.wangcong@gmail.com
Cong Wang [Sun, 4 Jul 2021 19:02:45 +0000 (12:02 -0700)]
af_unix: Set TCP_ESTABLISHED for datagram sockets too
Currently only unix stream socket sets TCP_ESTABLISHED,
datagram socket can set this too when they connect to its
peer socket. At least __ip4_datagram_connect() does the same.
This will be used to determine whether an AF_UNIX datagram
socket can be redirected to in sockmap.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210704190252.11866-5-xiyou.wangcong@gmail.com
Cong Wang [Sun, 4 Jul 2021 19:02:44 +0000 (12:02 -0700)]
af_unix: Implement ->read_sock() for sockmap
Implement ->read_sock() for AF_UNIX datagram socket, it is
pretty much similar to udp_read_sock().
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210704190252.11866-4-xiyou.wangcong@gmail.com
Cong Wang [Sun, 4 Jul 2021 19:02:43 +0000 (12:02 -0700)]
sock_map: Lift socket state restriction for datagram sockets
TCP and other connection oriented sockets have accept()
for each incoming connection on the server side, hence
they can just insert those fd's from accept() to sockmap,
which are of course established.
Now with datagram sockets begin to support sockmap and
redirection, the restriction is no longer applicable to
them, as they have no accept(). So we have to lift this
restriction for them. This is fine, because inside
bpf_sk_redirect_map() we still have another socket status
check, sock_map_redirect_allowed(), as a guard.
This also means they do not have to be removed from
sockmap when disconnecting.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210704190252.11866-3-xiyou.wangcong@gmail.com
Cong Wang [Sun, 4 Jul 2021 19:02:42 +0000 (12:02 -0700)]
sock_map: Relax config dependency to CONFIG_NET
Currently sock_map still has Kconfig dependency on CONFIG_INET,
but there is no actual functional dependency on it after we
introduce ->psock_update_sk_prot().
We have to extend it to CONFIG_NET now as we are going to
support AF_UNIX.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210704190252.11866-2-xiyou.wangcong@gmail.com
Alexei Starovoitov [Fri, 16 Jul 2021 00:17:43 +0000 (17:17 -0700)]
Merge branch 'Add bpf_get_func_ip helper'
Jiri Olsa says:
====================
Add bpf_get_func_ip helper that returns IP address of the
caller function for trampoline and krobe programs.
There're 2 specific implementation of the bpf_get_func_ip
helper, one for trampoline progs and one for kprobe/kretprobe
progs.
The trampoline helper call is replaced/inlined by the verifier
with simple move instruction. The kprobe/kretprobe is actual
helper call that returns prepared caller address.
Also available at:
https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
bpf/get_func_ip
v4 changes:
- dropped jit/x86 check for get_func_ip tracing check [Alexei]
- added code to bpf_get_func_ip_tracing [Alexei]
and tested that it works without inlining [Alexei]
- changed has_get_func_ip to check_get_func_ip [Andrii]
- replaced test assert loop with explicit asserts [Andrii]
- adde bpf_program__attach_kprobe_opts function
and use it for offset setup [Andrii]
- used bpf_program__set_autoload(false) for test6 [Andrii]
- added Masami's ack
v3 changes:
- resend with Masami in cc and v3 in each patch subject
v2 changes:
- use kprobe_running to get kprobe instead of cpu var [Masami]
- added support to add kprobe on function+offset
and test for that [Alan]
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Jiri Olsa [Wed, 14 Jul 2021 09:44:00 +0000 (11:44 +0200)]
selftests/bpf: Add test for bpf_get_func_ip in kprobe+offset probe
Adding test for bpf_get_func_ip in kprobe+ofset probe.
Because of the offset value it's arch specific, enabling
the new test only for x86_64 architecture.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210714094400.396467-9-jolsa@kernel.org
Alan Maguire [Wed, 14 Jul 2021 09:43:59 +0000 (11:43 +0200)]
libbpf: Allow specification of "kprobe/function+offset"
kprobes can be placed on most instructions in a function, not
just entry, and ftrace and bpftrace support the function+offset
notification for probe placement. Adding parsing of func_name
into func+offset to bpf_program__attach_kprobe() allows the
user to specify
SEC("kprobe/bpf_fentry_test5+0x6")
...for example, and the offset can be passed to perf_event_open_probe()
to support kprobe attachment.
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210714094400.396467-8-jolsa@kernel.org
Jiri Olsa [Wed, 14 Jul 2021 09:43:58 +0000 (11:43 +0200)]
libbpf: Add bpf_program__attach_kprobe_opts function
Adding bpf_program__attach_kprobe_opts that does the same
as bpf_program__attach_kprobe, but takes opts argument.
Currently opts struct holds just retprobe bool, but we will
add new field in following patch.
The function is not exported, so there's no need to add
size to the struct bpf_program_attach_kprobe_opts for now.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210714094400.396467-7-jolsa@kernel.org
Jiri Olsa [Wed, 14 Jul 2021 09:43:57 +0000 (11:43 +0200)]
selftests/bpf: Add test for bpf_get_func_ip helper
Adding test for bpf_get_func_ip helper for fentry, fexit,
kprobe, kretprobe and fmod_ret programs.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210714094400.396467-6-jolsa@kernel.org
Jiri Olsa [Wed, 14 Jul 2021 09:43:56 +0000 (11:43 +0200)]
bpf: Add bpf_get_func_ip helper for kprobe programs
Adding bpf_get_func_ip helper for BPF_PROG_TYPE_KPROBE programs,
so it's now possible to call bpf_get_func_ip from both kprobe and
kretprobe programs.
Taking the caller's address from 'struct kprobe::addr', which is
defined for both kprobe and kretprobe.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/bpf/20210714094400.396467-5-jolsa@kernel.org
Jiri Olsa [Wed, 14 Jul 2021 09:43:55 +0000 (11:43 +0200)]
bpf: Add bpf_get_func_ip helper for tracing programs
Adding bpf_get_func_ip helper for BPF_PROG_TYPE_TRACING programs,
specifically for all trampoline attach types.
The trampoline's caller IP address is stored in (ctx - 8) address.
so there's no reason to actually call the helper, but rather fixup
the call instruction and return [ctx - 8] value directly.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210714094400.396467-4-jolsa@kernel.org
Jiri Olsa [Wed, 14 Jul 2021 09:43:54 +0000 (11:43 +0200)]
bpf: Enable BPF_TRAMP_F_IP_ARG for trampolines with call_get_func_ip
Enabling BPF_TRAMP_F_IP_ARG for trampolines that actually need it.
The BPF_TRAMP_F_IP_ARG adds extra 3 instructions to trampoline code
and is used only by programs with bpf_get_func_ip helper, which is
added in following patch and sets call_get_func_ip bit.
This patch ensures that BPF_TRAMP_F_IP_ARG flag is used only for
trampolines that have programs with call_get_func_ip set.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210714094400.396467-3-jolsa@kernel.org
Jiri Olsa [Wed, 14 Jul 2021 09:43:53 +0000 (11:43 +0200)]
bpf, x86: Store caller's ip in trampoline stack
Storing caller's ip in trampoline's stack. Trampoline programs
can reach the IP in (ctx - 8) address, so there's no change in
program's arguments interface.
The IP address is takes from [fp + 8], which is return address
from the initial 'call fentry' call to trampoline.
This IP address will be returned via bpf_get_func_ip helper
helper, which is added in following patches.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210714094400.396467-2-jolsa@kernel.org
Daniel Borkmann [Thu, 15 Jul 2021 20:33:04 +0000 (22:33 +0200)]
Merge branch 'bpf-timers'
Alexei Starovoitov says:
====================
The first request to support timers in bpf was made in 2013 before sys_bpf
syscall was added. That use case was periodic sampling. It was address with
attaching bpf programs to perf_events. Then during XDP development the timers
were requested to do garbage collection and health checks. They were worked
around by implementing timers in user space and triggering progs with
BPF_PROG_RUN command. The user space timers and perf_event+bpf timers are not
armed by the bpf program. They're done asynchronously vs program execution.
The XDP program cannot send a packet and arm the timer at the same time. The
tracing prog cannot record an event and arm the timer right away. This large
class of use cases remained unaddressed. The jiffy based and hrtimer based
timers are essential part of the kernel development and with this patch set
the hrtimer based timers will be available to bpf programs.
TLDR: bpf timers is a wrapper of hrtimers with all the extra safety added
to make sure bpf progs cannot crash the kernel.
v6->v7:
- address Andrii's comments and add his Acks.
v5->v6:
- address code review feedback from Martin and add his Acks.
- add usercnt > 0 check to bpf_timer_init and remove timers_cancel_and_free
second loop in map_free callbacks.
- add cond_resched_rcu.
v4->v5:
- Martin noticed the following issues:
. prog could be reallocated bpf_patch_insn_data().
Fixed by passing 'aux' into bpf_timer_set_callback, since 'aux' is stable
during insn patching.
. Added missing rcu_read_lock.
. Removed redundant record_map.
- Discovered few bugs with stress testing:
. One cpu does htab_free_prealloced_timers->bpf_timer_cancel_and_free->hrtimer_cancel
while another is trying to do something with the timer like bpf_timer_start/set_callback.
Those ops try to acquire bpf_spin_lock that is already taken by bpf_timer_cancel_and_free,
so both cpus spin forever. The same problem existed in bpf_timer_cancel().
One bpf prog on one cpu might call bpf_timer_cancel and wait, while another cpu is in
the timer callback that tries to do bpf_timer_*() helper on the same timer.
The fix is to do drop_prog_refcnt() and unlock. And only then hrtimer_cancel.
Because of this had to add callback_fn != NULL check to bpf_timer_cb().
Also removed redundant bpf_prog_inc/put from bpf_timer_cb() and replaced
with rcu_dereference_check similar to recent rcu_read_lock-removal from drivers.
bpf_timer_cb is in softirq.
. Managed to hit refcnt==0 while doing bpf_prog_put from bpf_timer_cancel_and_free().
That exposed the issue that bpf_prog_put wasn't ready to be called from irq context.
Fixed similar to bpf_map_put which is irq ready.
- Refactored BPF_CALL_1(bpf_spin_lock) into __bpf_spin_lock_irqsave() to
make the main logic more clear, since Martin and Yonghong brought up this concern.
v3->v4:
1.
Split callback_fn from bpf_timer_start into bpf_timer_set_callback as
suggested by Martin. That makes bpf timer api match one to one to
kernel hrtimer api and provides greater flexibility.
2.
Martin also discovered the following issue with uref approach:
bpftool prog load xdp_timer.o /sys/fs/bpf/xdp_timer type xdp
bpftool net attach xdpgeneric pinned /sys/fs/bpf/xdp_timer dev lo
rm /sys/fs/bpf/xdp_timer
nc -6 ::1 8888
bpftool net detach xdpgeneric dev lo
The timer callback stays active in the kernel though the prog was detached
and map usercnt == 0.
It happened because 'bpftool prog load' pinned the prog only.
The map usercnt went to zero. Subsequent attach and runs didn't
affect map usercnt. The timer was able to start and bpf_prog_inc itself.
When the prog was detached the prog stayed active.
To address this issue added
if (!atomic64_read(&(t->map->usercnt))) return -EPERM;
to the first patch.
Which means that timers are allowed only in the maps that are held
by user space with open file descriptor or maps pinned in bpffs.
3.
Discovered that timers in inner maps were broken.
The inner map pointers are dynamic. Therefore changed bpf_timer_init()
to accept explicit map pointer supplied by the program instead
of hidden map pointer supplied by the verifier.
To make sure that pointer to a timer actually belongs to that map
added the verifier check in patch 3.
4.
Addressed Yonghong's feedback. Improved comments and added
dynamic in_nmi() check.
Added Acks.
v2->v3:
The v2 approach attempted to bump bpf_prog refcnt when bpf_timer_start is
called to make sure callback code doesn't disappear when timer is active and
drop refcnt when timer cb is done. That led to a ton of race conditions between
callback running and concurrent bpf_timer_init/start/cancel on another cpu,
and concurrent bpf_map_update/delete_elem, and map destroy.
Then v2.5 approach skipped prog refcnt altogether. Instead it remembered all
timers that bpf prog armed in a link list and canceled them when prog refcnt
went to zero. The race conditions disappeared, but timers in map-in-map could
not be supported cleanly, since timers in inner maps have inner map's life time
and don't match prog's life time.
This v3 approach makes timers to be owned by maps. It allows timers in inner
maps to be supported from the start. This apporach relies on "user refcnt"
scheme used in prog_array that stores bpf programs for bpf_tail_call. The
bpf_timer_start() increments prog refcnt, but unlike 1st approach the timer
callback does decrement the refcnt. The ops->map_release_uref is
responsible for cancelling the timers and dropping prog refcnt when user space
reference to a map is dropped. That addressed all the races and simplified
locking.
Andrii presented a use case where specifying callback_fn in bpf_timer_init()
is inconvenient vs specifying in bpf_timer_start(). The bpf_timer_init()
typically is called outside for timer callback, while bpf_timer_start() most
likely will be called from the callback.
timer_cb() { ... bpf_timer_start(timer_cb); ...} looks like recursion and as
infinite loop to the verifier. The verifier had to be made smarter to recognize
such async callbacks. Patches 7,8,9 addressed that.
Patch 1 and 2 refactoring.
Patch 3 implements bpf timer helpers and locking.
Patch 4 implements map side of bpf timer support.
Patch 5 prevent pointer mismatch in bpf_timer_init.
Patch 6 adds support for BTF in inner maps.
Patch 7 teaches check_cfg() pass to understand async callbacks.
Patch 8 teaches do_check() pass to understand async callbacks.
Patch 9 teaches check_max_stack_depth() pass to understand async callbacks.
Patches 10 and 11 are the tests.
v1->v2:
- Addressed great feedback from Andrii and Toke.
- Fixed race between parallel bpf_timer_*() ops.
- Fixed deadlock between timer callback and LRU eviction or bpf_map_delete/update.
- Disallowed mmap and global timers.
- Allow spin_lock and bpf_timer in an element.
- Fixed memory leaks due to map destruction and LRU eviction.
- A ton more tests.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Alexei Starovoitov [Thu, 15 Jul 2021 00:54:17 +0000 (17:54 -0700)]
selftests/bpf: Add a test with bpf_timer in inner map.
Check that map-in-map supports bpf timers.
Check that indirect "recursion" of timer callbacks works:
timer_cb1() { bpf_timer_set_callback(timer_cb2); }
timer_cb2() { bpf_timer_set_callback(timer_cb1); }
Check that
bpf_map_release
htab_free_prealloced_timers
bpf_timer_cancel_and_free
hrtimer_cancel
works while timer cb is running.
"while true; do ./test_progs -t timer_mim; done"
is a great stress test. It caught missing timer cancel in htab->extra_elems.
timer_mim_reject.c is a negative test that checks
that timer<->map mismatch is prevented.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210715005417.78572-12-alexei.starovoitov@gmail.com
Alexei Starovoitov [Thu, 15 Jul 2021 00:54:16 +0000 (17:54 -0700)]
selftests/bpf: Add bpf_timer test.
Add bpf_timer test that creates timers in preallocated and
non-preallocated hash, in array and in lru maps.
Let array timer expire once and then re-arm it for 35 seconds.
Arm lru timer into the same callback.
Then arm and re-arm hash timers 10 times each.
At the last invocation of prealloc hash timer cancel the array timer.
Force timer free via LRU eviction and direct bpf_map_delete_elem.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210715005417.78572-11-alexei.starovoitov@gmail.com
Alexei Starovoitov [Thu, 15 Jul 2021 00:54:15 +0000 (17:54 -0700)]
bpf: Teach stack depth check about async callbacks.
Teach max stack depth checking algorithm about async callbacks
that don't increase bpf program stack size.
Also add sanity check that bpf_tail_call didn't sneak into async cb.
It's impossible, since PTR_TO_CTX is not available in async cb,
hence the program cannot contain bpf_tail_call(ctx,...);
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210715005417.78572-10-alexei.starovoitov@gmail.com
Alexei Starovoitov [Thu, 15 Jul 2021 00:54:14 +0000 (17:54 -0700)]
bpf: Implement verifier support for validation of async callbacks.
bpf_for_each_map_elem() and bpf_timer_set_callback() helpers are relying on
PTR_TO_FUNC infra in the verifier to validate addresses to subprograms
and pass them into the helpers as function callbacks.
In case of bpf_for_each_map_elem() the callback is invoked synchronously
and the verifier treats it as a normal subprogram call by adding another
bpf_func_state and new frame in __check_func_call().
bpf_timer_set_callback() doesn't invoke the callback directly.
The subprogram will be called asynchronously from bpf_timer_cb().
Teach the verifier to validate such async callbacks as special kind
of jump by pushing verifier state into stack and let pop_stack() process it.
Special care needs to be taken during state pruning.
The call insn doing bpf_timer_set_callback has to be a prune_point.
Otherwise short timer callbacks might not have prune points in front of
bpf_timer_set_callback() which means is_state_visited() will be called
after this call insn is processed in __check_func_call(). Which means that
another async_cb state will be pushed to be walked later and the verifier
will eventually hit BPF_COMPLEXITY_LIMIT_JMP_SEQ limit.
Since push_async_cb() looks like another push_stack() branch the
infinite loop detection will trigger false positive. To recognize
this case mark such states as in_async_callback_fn.
To distinguish infinite loop in async callback vs the same callback called
with different arguments for different map and timer add async_entry_cnt
to bpf_func_state.
Enforce return zero from async callbacks.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210715005417.78572-9-alexei.starovoitov@gmail.com
Alexei Starovoitov [Thu, 15 Jul 2021 00:54:13 +0000 (17:54 -0700)]
bpf: Relax verifier recursion check.
In the following bpf subprogram:
static int timer_cb(void *map, void *key, void *value)
{
bpf_timer_set_callback(.., timer_cb);
}
the 'timer_cb' is a pointer to a function.
ld_imm64 insn is used to carry this pointer.
bpf_pseudo_func() returns true for such ld_imm64 insn.
Unlike bpf_for_each_map_elem() the bpf_timer_set_callback() is asynchronous.
Relax control flow check to allow such "recursion" that is seen as an infinite
loop by check_cfg(). The distinction between bpf_for_each_map_elem() the
bpf_timer_set_callback() is done in the follow up patch.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210715005417.78572-8-alexei.starovoitov@gmail.com