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| author | Romain Perier <romain.perier@free-electrons.com> | 2016-04-14 15:36:03 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2016-04-21 11:06:09 +0200 |
| commit | fba7cd681b6155e2d93e7862fcd6f970336b83c3 (patch) | |
| tree | 7204cd2e2e821bde02b0279fd610b7139e82d51d /include/asm-generic | |
| parent | fe1bce9e2107ba3a8faffe572483b6974201a0e6 (diff) | |
| download | linux-fba7cd681b6155e2d93e7862fcd6f970336b83c3.tar.bz2 | |
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 <romain.perier@free-electrons.com>
Cc: linux-arch@vger.kernel.org
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1460640963-690-1-git-send-email-romain.perier@free-electrons.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/asm-generic')
| -rw-r--r-- | include/asm-generic/futex.h | 8 |
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(); |