tcp: Fix possible double-ack w/ user dma

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

diff --git a/kernel/exit.c b/kernel/exit.c
index 25ed2ad986dffb430ae005727a48f91941a3ff5a..85a83c831856c193570e40a3b7d3e03ef8862d1c 100644 (file)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -112,9 +112,9 @@ static void __exit_signal(struct task_struct *tsk)
                 * We won't ever get here for the group leader, since it
                 * will have been the last reference on the signal_struct.
                 */
-               sig->utime = cputime_add(sig->utime, tsk->utime);
-               sig->stime = cputime_add(sig->stime, tsk->stime);
-               sig->gtime = cputime_add(sig->gtime, tsk->gtime);
+               sig->utime = cputime_add(sig->utime, task_utime(tsk));
+               sig->stime = cputime_add(sig->stime, task_stime(tsk));
+               sig->gtime = cputime_add(sig->gtime, task_gtime(tsk));
                sig->min_flt += tsk->min_flt;
                sig->maj_flt += tsk->maj_flt;
                sig->nvcsw += tsk->nvcsw;
@@ -583,8 +583,6 @@ mm_need_new_owner(struct mm_struct *mm, struct task_struct *p)
         * If there are other users of the mm and the owner (us) is exiting
         * we need to find a new owner to take on the responsibility.
         */
-       if (!mm)
-               return 0;
        if (atomic_read(&mm->mm_users) <= 1)
                return 0;
        if (mm->owner != p)
@@ -627,6 +625,16 @@ retry:
        } while_each_thread(g, c);
 
        read_unlock(&tasklist_lock);
+       /*
+        * We found no owner yet mm_users > 1: this implies that we are
+        * most likely racing with swapoff (try_to_unuse()) or /proc or
+        * ptrace or page migration (get_task_mm()).  Mark owner as NULL,
+        * so that subsystems can understand the callback and take action.
+        */
+       down_write(&mm->mmap_sem);
+       cgroup_mm_owner_callbacks(mm->owner, NULL);
+       mm->owner = NULL;
+       up_write(&mm->mmap_sem);
        return;
 
 assign_new_owner: