diff options
Diffstat (limited to 'kernel/exit.c')
| -rw-r--r-- | kernel/exit.c | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 87a2d515de0d..3594291a8542 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -454,7 +454,10 @@ static void exit_mm(void) mmap_read_unlock(mm); self.task = current; - self.next = xchg(&core_state->dumper.next, &self); + if (self.task->flags & PF_SIGNALED) + self.next = xchg(&core_state->dumper.next, &self); + else + self.task = NULL; /* * Implies mb(), the result of xchg() must be visible * to core_state->dumper. @@ -475,10 +478,24 @@ static void exit_mm(void) BUG_ON(mm != current->active_mm); /* more a memory barrier than a real lock */ task_lock(current); + /* + * When a thread stops operating on an address space, the loop + * in membarrier_private_expedited() may not observe that + * tsk->mm, and the loop in membarrier_global_expedited() may + * not observe a MEMBARRIER_STATE_GLOBAL_EXPEDITED + * rq->membarrier_state, so those would not issue an IPI. + * Membarrier requires a memory barrier after accessing + * user-space memory, before clearing tsk->mm or the + * rq->membarrier_state. + */ + smp_mb__after_spinlock(); + local_irq_disable(); current->mm = NULL; - mmap_read_unlock(mm); + membarrier_update_current_mm(NULL); enter_lazy_tlb(mm, current); + local_irq_enable(); task_unlock(current); + mmap_read_unlock(mm); mm_update_next_owner(mm); mmput(mm); if (test_thread_flag(TIF_MEMDIE)) |