Commit-ID: 39919b01ae4c1949736b40b79e27178d0c0bc406 Gitweb: http://git.kernel.org/tip/39919b01ae4c1949736b40b79e27178d0c0bc406 Author: David Hildenbrand <d...@linux.vnet.ibm.com> AuthorDate: Mon, 11 May 2015 17:52:15 +0200 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Tue, 19 May 2015 08:39:16 +0200
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 <t...@linutronix.de> Signed-off-by: David Hildenbrand <d...@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: david.lai...@aculab.com Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: airl...@linux.ie Cc: a...@linux-foundation.org Cc: b...@kernel.crashing.org Cc: bige...@linutronix.de Cc: borntrae...@de.ibm.com Cc: daniel.vet...@intel.com Cc: heiko.carst...@de.ibm.com Cc: herb...@gondor.apana.org.au Cc: ho...@suse.cz Cc: hu...@google.com Cc: m...@redhat.com Cc: pau...@samba.org Cc: r...@linux-mips.org Cc: schwidef...@de.ibm.com Cc: yang....@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-11-git-send-email-d...@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/arm/include/asm/futex.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm/include/asm/futex.h b/arch/arm/include/asm/futex.h index 4e78065..255bfd1 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; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
