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| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-05-15 13:02:23 +0300 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-05-15 13:06:35 +0300 |
| commit | 1b97937246d8b97c0760d16d8992c7937bdf5e6a (patch) | |
| tree | c1a283d279d553bf0b1b975ee280efe202e0087a /arch/arm/kernel/entry-common.S | |
| parent | 965278dcb8ab0b1f666cc47937933c4be4aea48d (diff) | |
| download | linux-1b97937246d8b97c0760d16d8992c7937bdf5e6a.tar.xz | |
ARM: fix missing syscall trace exit
Josh Stone reports:
I've discovered a case where both arm and arm64 will miss a ptrace
syscall-exit that they should report. If the syscall is entered
without TIF_SYSCALL_TRACE set, then it goes on the fast path. It's
then possible to have TIF_SYSCALL_TRACE added in the middle of the
syscall, but ret_fast_syscall doesn't check this flag again.
Fix this by always checking for a syscall trace in the fast exit path.
Reported-by: Josh Stone <jistone@redhat.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/entry-common.S')
| -rw-r--r-- | arch/arm/kernel/entry-common.S | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index f8ccc21fa032..4e7f40c577e6 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -33,7 +33,9 @@ ret_fast_syscall: UNWIND(.fnstart ) UNWIND(.cantunwind ) disable_irq @ disable interrupts - ldr r1, [tsk, #TI_FLAGS] + ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing + tst r1, #_TIF_SYSCALL_WORK + bne __sys_trace_return tst r1, #_TIF_WORK_MASK bne fast_work_pending asm_trace_hardirqs_on |