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Merge branch 'for-4.10-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

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Pull percpu fix from Tejun Heo:
 "Douglas found and fixed a ref leak bug in percpu_ref_tryget[_live]().

  The bug is caused by storing the return value of atomic_long_inc_not_zero()
  into an int temp variable before returning it as a bool. The interim
  cast to int loses the upper bits and can lead to false negatives. As
  percpu_ref uses a high bit to mark a draining counter, this can happen
  relatively easily.

  Fixed by using bool for the temp variable"

* 'for-4.10-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu-refcount: fix reference leak during percpu-atomic transition
This commit is contained in:
Linus Torvalds 2017-01-31 13:10:59 -08:00
parent 52e02f2797 966d2b04e0
commit 298a2d8751
1 changed files with 2 additions and 2 deletions
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4
include/linux/percpu-refcount.h
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@ -204,7 +204,7 @@ static inline void percpu_ref_get(struct percpu_ref *ref)
static inline bool percpu_ref_tryget(struct percpu_ref *ref)
{
unsigned long __percpu *percpu_count;
int ret;
bool ret;
rcu_read_lock_sched();
@ -238,7 +238,7 @@ static inline bool percpu_ref_tryget(struct percpu_ref *ref)
static inline bool percpu_ref_tryget_live(struct percpu_ref *ref)
{
unsigned long __percpu *percpu_count;
int ret = false;
bool ret = false;
rcu_read_lock_sched();