This is a note to let you know that I've just added the patch titled
arm64: spinlock: retry trylock operation if strex fails on free lock
to the 3.10-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:
arm64-spinlock-retry-trylock-operation-if-strex-fails-on-free-lock.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4ecf7ccb1973fd826456b6ab1e6dfafe9023c753 Mon Sep 17 00:00:00 2001
From: Catalin Marinas <catalin.marinas@xxxxxxx>
Date: Fri, 31 May 2013 16:30:58 +0100
Subject: arm64: spinlock: retry trylock operation if strex fails on free lock
From: Catalin Marinas <catalin.marinas@xxxxxxx>
commit 4ecf7ccb1973fd826456b6ab1e6dfafe9023c753 upstream.
An exclusive store instruction may fail for reasons other than lock
contention (e.g. a cache eviction during the critical section) so, in
line with other architectures using similar exclusive instructions
(alpha, mips, powerpc), retry the trylock operation if the lock appears
to be free but the strex reported failure.
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Reported-by: Tony Thompson <anthony.thompson@xxxxxxx>
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/spinlock.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/arm64/include/asm/spinlock.h
+++ b/arch/arm64/include/asm/spinlock.h
@@ -59,9 +59,10 @@ static inline int arch_spin_trylock(arch
unsigned int tmp;
asm volatile(
- " ldaxr %w0, %1\n"
+ "2: ldaxr %w0, %1\n"
" cbnz %w0, 1f\n"
" stxr %w0, %w2, %1\n"
+ " cbnz %w0, 2b\n"
"1:\n"
: "=&r" (tmp), "+Q" (lock->lock)
: "r" (1)
Patches currently in stable-queue which might be from catalin.marinas@xxxxxxx are
queue-3.10/arm64-ptrace-avoid-using-hw_breakpoint_empty-for-disabled-events.patch
queue-3.10/arm64-spinlock-retry-trylock-operation-if-strex-fails-on-free-lock.patch
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