Make sure "user->sigpending" count is in sync

[linux-2.6-omap-h63xx.git] / kernel / signal.c

diff --git a/kernel/signal.c b/kernel/signal.c
index 7ed8d5304bec2d2c9e51099f5c66ff304d40946a..df18c167a2a72d67d76cabc1768b741c12ed5e7e 100644 (file)
--- 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);
 }