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authorRomain Perier <[email protected]>2016-04-14 15:36:03 +0200
committerThomas Gleixner <[email protected]>2016-04-21 11:06:09 +0200
commitfba7cd681b6155e2d93e7862fcd6f970336b83c3 (patch)
tree7204cd2e2e821bde02b0279fd610b7139e82d51d
parentfe1bce9e2107ba3a8faffe572483b6974201a0e6 (diff)
asm-generic/futex: Re-enable preemption in futex_atomic_cmpxchg_inatomic()
The recent decoupling of pagefault disable and preempt disable added an explicit preempt_disable/enable() pair to the futex_atomic_cmpxchg_inatomic() implementation in asm-generic/futex.h. But it forgot to add preempt_enable() calls to the error handling code pathes, which results in a preemption count imbalance. This is observable on boot when the test for atomic_cmpxchg() is calling futex_atomic_cmpxchg_inatomic() on a NULL pointer. Add the missing preempt_enable() calls to the error handling code pathes. [ tglx: Massaged changelog ] Fixes: d9b9ff8c1889 ("sched/preempt, futex: Disable preemption in UP futex_atomic_cmpxchg_inatomic() explicitly") Signed-off-by: Romain Perier <[email protected]> Cc: [email protected] Cc: Thomas Petazzoni <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]>
-rw-r--r--include/asm-generic/futex.h8
1 files changed, 6 insertions, 2 deletions
diff --git a/include/asm-generic/futex.h b/include/asm-generic/futex.h
index e56272c919b5..bf2d34c9d804 100644
--- a/include/asm-generic/futex.h
+++ b/include/asm-generic/futex.h
@@ -108,11 +108,15 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 val;
preempt_disable();
- if (unlikely(get_user(val, uaddr) != 0))
+ if (unlikely(get_user(val, uaddr) != 0)) {
+ preempt_enable();
return -EFAULT;
+ }
- if (val == oldval && unlikely(put_user(newval, uaddr) != 0))
+ if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) {
+ preempt_enable();
return -EFAULT;
+ }
*uval = val;
preempt_enable();