Revert "remove false BUG_ON() from run_posix_cpu_timers()"

This reverts commit 3de463c7d9d58f8cf3395268230cb20a4c15bffa.

Roland has another patch that allows us to leave the BUG_ON() in place
by just making sure that the condition it tests for really is always
true.

That goes in next.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/kernel/exit.c b/kernel/exit.c
index 4897977..3b25b18 100644 (file)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -825,6 +825,14 @@ 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 383ba22..ea1aca5 100644 (file)
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -1293,30 +1293,30 @@ 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);
-       if (likely(tsk->signal != NULL)) {
-               spin_lock(&tsk->sighand->siglock);
+       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);
 
        /*