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x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls
authorAndy Lutomirski <luto@kernel.org>
Thu, 4 Mar 2021 19:05:54 +0000 (11:05 -0800)
committerBorislav Petkov <bp@suse.de>
Sat, 6 Mar 2021 12:10:06 +0000 (13:10 +0100)
commit5d5675df792ff67e74a500c4c94db0f99e6a10ef
treee9b463d979b295c7f5f05efe5723937ad73aef65
parentb59cc97674c947861783ca92b9a6e7d043adba96
x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls

On a 32-bit fast syscall that fails to read its arguments from user
memory, the kernel currently does syscall exit work but not
syscall entry work.  This confuses audit and ptrace.  For example:

    $ ./tools/testing/selftests/x86/syscall_arg_fault_32
    ...
    strace: pid 264258: entering, ptrace_syscall_info.op == 2
    ...

This is a minimal fix intended for ease of backporting.  A more
complete cleanup is coming.

Fixes: 0b085e68f407 ("x86/entry: Consolidate 32/64 bit syscall entry")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/8c82296ddf803b91f8d1e5eac89e5803ba54ab0e.1614884673.git.luto@kernel.org
arch/x86/entry/common.c