diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/exit.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 1f7e7545e1d0..749da057424a 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -472,21 +472,29 @@ static inline void __exit_mm(struct task_struct * tsk) if (!mm) return; /* - * Serialize with any possible pending coredump: + * Serialize with any possible pending coredump. + * We must hold mmap_sem around checking core_waiters + * and clearing tsk->mm. The core-inducing thread + * will increment core_waiters for each thread in the + * group with ->mm != NULL. */ + down_read(&mm->mmap_sem); if (mm->core_waiters) { + up_read(&mm->mmap_sem); down_write(&mm->mmap_sem); if (!--mm->core_waiters) complete(mm->core_startup_done); up_write(&mm->mmap_sem); wait_for_completion(&mm->core_done); + down_read(&mm->mmap_sem); } atomic_inc(&mm->mm_count); if (mm != tsk->active_mm) BUG(); /* more a memory barrier than a real lock */ task_lock(tsk); tsk->mm = NULL; + up_read(&mm->mmap_sem); enter_lazy_tlb(mm, current); task_unlock(tsk); mmput(mm); |