@@ -447,7 +447,7 @@ static bool __oom_reap_task(struct task_struct *tsk)
struct task_struct *p;
struct zap_details details = {.check_swap_entries = true,
.ignore_dirty = true};
- bool ret = true;
+ bool ret;
/*
* We have to make sure to not race with the victim exit path
@@ -472,13 +472,16 @@ static bool __oom_reap_task(struct task_struct *tsk)
* is no mm.
*/
p = find_lock_task_mm(tsk);
- if (!p)
- goto unlock_oom;
+ if (!p) {
+ mutex_unlock(&oom_lock);
+ return true;
+ }
mm = p->mm;
if (!atomic_inc_not_zero(&mm->mm_users)) {
task_unlock(p);
- goto unlock_oom;
+ mutex_unlock(&oom_lock);
+ return true;
}
task_unlock(p);
@@ -527,6 +530,7 @@ static bool __oom_reap_task(struct task_struct *tsk)
* to release its memory.
*/
set_bit(MMF_OOM_REAPED, &mm->flags);
+ ret = true;
unlock_oom:
mutex_unlock(&oom_lock);
/*
The change to the oom_reaper to hold a mutex inside __oom_reap_task() accidentally started calling mmput_async() on the local mm before that variable got initialized, as reported by gcc in linux-next: mm/oom_kill.c: In function '__oom_reap_task': mm/oom_kill.c:537:2: error: 'mm' may be used uninitialized in this function [-Werror=maybe-uninitialized] This rearranges the code slightly back to the state before patch but leaves the lock in place. The error handling in the function still looks a bit confusing and could probably be improved but I could not come up with a solution that made me happy for now. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Fixes: mmotm ("oom_reaper: close race with exiting task") --- mm/oom_kill.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) -- 2.7.0