diff options
| -rw-r--r-- | lib/is_single_threaded.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/lib/is_single_threaded.c b/lib/is_single_threaded.c index 434010980bd..bd2bea96336 100644 --- a/lib/is_single_threaded.c +++ b/lib/is_single_threaded.c @@ -22,8 +22,6 @@ bool current_is_single_threaded(void) struct task_struct *p, *t; bool ret; - might_sleep(); - if (atomic_read(&task->signal->live) != 1) return false; @@ -31,7 +29,6 @@ bool current_is_single_threaded(void) return true; ret = false; - down_write(&mm->mmap_sem); rcu_read_lock(); for_each_process(p) { if (unlikely(p->flags & PF_KTHREAD)) @@ -45,12 +42,17 @@ bool current_is_single_threaded(void) goto found; if (likely(t->mm)) break; + /* + * t->mm == NULL. Make sure next_thread/next_task + * will see other CLONE_VM tasks which might be + * forked before exiting. + */ + smp_rmb(); } while_each_thread(p, t); } ret = true; found: rcu_read_unlock(); - up_write(&mm->mmap_sem); return ret; } |