merge linus into release branch

2 files changed, 22 insertions, 34 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index e95b932822..e06d0c10a2 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -881,14 +881,6 @@ fastcall NORET_TYPE void do_exit(long code)
 
         tsk->flags |= PF_EXITING;
 
-        /*
-         * Make sure we don't try to process any timer firings
-         * while we are already exiting.
-         */
-        tsk->it_virt_expires = cputime_zero;
-        tsk->it_prof_expires = cputime_zero;
-        tsk->it_sched_expires = 0;
-
         if (unlikely(in_atomic()))
                 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
                                 current->comm, current->pid,
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 520f6c5994..d38d9ec327 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -555,9 +555,6 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
         struct cpu_timer_list *next;
         unsigned long i;
 
-        if (CPUCLOCK_PERTHREAD(timer->it_clock) && (p->flags & PF_EXITING))
-                return;
-
         head = (CPUCLOCK_PERTHREAD(timer->it_clock) ?
                 p->cpu_timers : p->signal->cpu_timers);
         head += CPUCLOCK_WHICH(timer->it_clock);
@@ -1173,6 +1170,9 @@ static void check_process_timers(struct task_struct *tsk,
                 }
                 t = tsk;
                 do {
+                        if (unlikely(t->flags & PF_EXITING))
+                                continue;
+
                         ticks = cputime_add(cputime_add(t->utime, t->stime),
                                             prof_left);
                         if (!cputime_eq(prof_expires, cputime_zero) &&
@@ -1193,11 +1193,7 @@ static void check_process_timers(struct task_struct *tsk,
                                               t->it_sched_expires > sched)) {
                                 t->it_sched_expires = sched;
                         }
-
-                        do {
-                                t = next_thread(t);
-                        } while (unlikely(t->flags & PF_EXITING));
-                } while (t != tsk);
+                } while ((t = next_thread(t)) != tsk);
         }
 }
 
@@ -1289,30 +1285,30 @@ void run_posix_cpu_timers(struct task_struct *tsk)
 
 #undef  UNEXPIRED
 
-        BUG_ON(tsk->exit_state);
-
         /*
          * Double-check with locks held.
          */
         read_lock(&tasklist_lock);
-        spin_lock(&tsk->sighand->siglock);
+        if (likely(tsk->signal != NULL)) {
+                spin_lock(&tsk->sighand->siglock);
 
-        /*
-         * Here we take off tsk->cpu_timers[N] and tsk->signal->cpu_timers[N]
-         * all the timers that are firing, and put them on the firing list.
-         */
-        check_thread_timers(tsk, &firing);
-        check_process_timers(tsk, &firing);
+                /*
+                 * Here we take off tsk->cpu_timers[N] and tsk->signal->cpu_timers[N]
+                 * all the timers that are firing, and put them on the firing list.
+                 */
+                check_thread_timers(tsk, &firing);
+                check_process_timers(tsk, &firing);
 
-        /*
-         * We must release these locks before taking any timer's lock.
-         * There is a potential race with timer deletion here, as the
-         * siglock now protects our private firing list.  We have set
-         * the firing flag in each timer, so that a deletion attempt
-         * that gets the timer lock before we do will give it up and
-         * spin until we've taken care of that timer below.
-         */
-        spin_unlock(&tsk->sighand->siglock);
+                /*
+                 * We must release these locks before taking any timer's lock.
+                 * There is a potential race with timer deletion here, as the
+                 * siglock now protects our private firing list.  We have set
+                 * the firing flag in each timer, so that a deletion attempt
+                 * that gets the timer lock before we do will give it up and
+                 * spin until we've taken care of that timer below.
+                 */
+                spin_unlock(&tsk->sighand->siglock);
+        }
         read_unlock(&tasklist_lock);
 
         /*