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| author | David Hildenbrand <dahi@linux.vnet.ibm.com> | 2015-05-11 17:52:15 +0200 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2015-11-18 11:10:39 -0800 |
| commit | 9dc4a5447b27904f75a6daa1d394786fd7acbff5 (patch) | |
| tree | 0e7229bf78cd810b21c5bdd7363da6b788479da0 | |
| parent | 8deb4ad469717839e0f181b9477f4b848aadfcdf (diff) | |
| download | v4.1-9dc4a5447b27904f75a6daa1d394786fd7acbff5.tar.gz | |
UPSTREAM: sched/preempt, arm/futex: Disable preemption in UP futex_atomic_cmpxchg_inatomic() explicitly
The !CONFIG_SMP implementation of futex_atomic_cmpxchg_inatomic()
requires preemption to be disabled to guarantee mutual exclusion.
Let's make this explicit.
This patch is based on a patch by Sebastian Andrzej Siewior on the
-rt branch.
Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: airlied@linux.ie
Cc: akpm@linux-foundation.org
Cc: benh@kernel.crashing.org
Cc: bigeasy@linutronix.de
Cc: borntraeger@de.ibm.com
Cc: daniel.vetter@intel.com
Cc: heiko.carstens@de.ibm.com
Cc: herbert@gondor.apana.org.au
Cc: hocko@suse.cz
Cc: hughd@google.com
Cc: mst@redhat.com
Cc: paulus@samba.org
Cc: ralf@linux-mips.org
Cc: schwidefsky@de.ibm.com
Cc: yang.shi@windriver.com
Link: http://lkml.kernel.org/r/1431359540-32227-11-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Bug: 25672827
Patchset: PAN emulation
(cherry picked from commit 39919b01ae4c1949736b40b79e27178d0c0bc406)
Signed-off-by: Kees Cook <keescook@google.com>
Change-Id: Iaf1f4cb9b81607be9835ee8bb53d11cec36089d7
| -rw-r--r-- | arch/arm/include/asm/futex.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm/include/asm/futex.h b/arch/arm/include/asm/futex.h index 4e78065a16a..255bfd15eda 100644 --- a/arch/arm/include/asm/futex.h +++ b/arch/arm/include/asm/futex.h @@ -93,6 +93,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) return -EFAULT; + preempt_disable(); __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" "1: " TUSER(ldr) " %1, [%4]\n" " teq %1, %2\n" @@ -104,6 +105,8 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, : "cc", "memory"); *uval = val; + preempt_enable(); + return ret; } |