diff --git a/kernel/signal.c b/kernel/signal.c index 7ed8d5304bec2d2c9e51099f5c66ff304d40946a..df18c167a2a72d67d76cabc1768b741c12ed5e7e 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -267,18 +267,25 @@ static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, int override_rlimit) { struct sigqueue *q = NULL; + struct user_struct *user; - atomic_inc(&t->user->sigpending); + /* + * In order to avoid problems with "switch_user()", we want to make + * sure that the compiler doesn't re-load "t->user" + */ + user = t->user; + barrier(); + atomic_inc(&user->sigpending); if (override_rlimit || - atomic_read(&t->user->sigpending) <= + atomic_read(&user->sigpending) <= t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) q = kmem_cache_alloc(sigqueue_cachep, flags); if (unlikely(q == NULL)) { - atomic_dec(&t->user->sigpending); + atomic_dec(&user->sigpending); } else { INIT_LIST_HEAD(&q->list); q->flags = 0; - q->user = get_uid(t->user); + q->user = get_uid(user); } return(q); }