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authorDavid Hildenbrand <dahi@linux.vnet.ibm.com>2015-05-11 18:52:14 +0300
committerIngo Molnar <mingo@kernel.org>2015-05-19 09:39:16 +0300
commitd9b9ff8c18891d74dc7076800bde81b774f7d032 (patch)
treece12138209e397d4fcbb1339990741dca7f2bfc9 /include/asm-generic
parentf3dae07e442a8131a5485b6a38db2aa22a7a48cf (diff)
downloadlinux-d9b9ff8c18891d74dc7076800bde81b774f7d032.tar.xz
sched/preempt, futex: Disable preemption in UP futex_atomic_cmpxchg_inatomic() explicitly
Let's explicitly disable/enable preemption in the !CONFIG_SMP version of futex_atomic_cmpxchg_inatomic(), to prepare for pagefault_disable() not touching preemption anymore. This is needed for this function to be callable from both, atomic and non-atomic context. Otherwise we might break mutual exclusion when relying on a get_user()/ put_user() implementation. 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/1431359540-32227-10-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/asm-generic')
-rw-r--r--include/asm-generic/futex.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/asm-generic/futex.h b/include/asm-generic/futex.h
index 358601750fe7..e56272c919b5 100644
--- a/include/asm-generic/futex.h
+++ b/include/asm-generic/futex.h
@@ -107,6 +107,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
{
u32 val;
+ preempt_disable();
if (unlikely(get_user(val, uaddr) != 0))
return -EFAULT;
@@ -114,6 +115,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
return -EFAULT;
*uval = val;
+ preempt_enable();
return 0;
}