This is a note to let you know that I've just added the patch titled
ARM: fix missing syscall trace exit
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-fix-missing-syscall-trace-exit.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1b97937246d8b97c0760d16d8992c7937bdf5e6a Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Date: Fri, 15 May 2015 11:02:23 +0100
Subject: ARM: fix missing syscall trace exit
From: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
commit 1b97937246d8b97c0760d16d8992c7937bdf5e6a upstream.
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@xxxxxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/kernel/entry-common.S | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -32,7 +32,9 @@ 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
Patches currently in stable-queue which might be from rmk+kernel@xxxxxxxxxxxxxxxx are
queue-3.14/arm-fix-missing-syscall-trace-exit.patch
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