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

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

Linus Torvalds committed 9 years ago

Commit 298a2d82 parents 52e02f2 966d2b01 file · +2 −2Browse files

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include/linux/percpu-refcount.h+2−2
@@ -204,7 +204,7 @@ static inline void percpu_ref_get(struct percpu_ref *ref) · 203 unmodified lines
204204 static inline bool percpu_ref_tryget(struct percpu_ref *ref)
205205 {
206206 unsigned long __percpu *percpu_count;
207− int ret;
207+ bool ret;
208208
209209 rcu_read_lock_sched();
210210
@@ -238,7 +238,7 @@ static inline bool percpu_ref_tryget(struct percpu_ref *ref) · 27 unmodified lines
238238 static inline bool percpu_ref_tryget_live(struct percpu_ref *ref)
239239 {
240240 unsigned long __percpu *percpu_count;
241− int ret = false;
241+ bool ret = false;
242242
243243 rcu_read_lock_sched();
244244