clockevent: Don't remove broadcast device when cpu is dead

commit ea9d8e3f45404d411c00ae67b45cc35c58265bb7 upstream.

Marc reported that the BUG_ON in clockevents_notify() triggers on his
system. This happens because the kernel tries to remove an active
clock event device (used for broadcasting) from the device list.

The handling of devices which can be used as per cpu device and as a
global broadcast device is suboptimal.

The simplest solution for now (and for stable) is to check whether the
device is used as global broadcast device, but this needs to be
revisited.

[ tglx: restored the cpuweight check and massaged the changelog ]

Reported-by: Marc Dionne <marc.c.dionne@gmail.com>
Tested-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
LKML-Reference: <1262834564-13033-1-git-send-email-dfeng@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 9484be456d69b8f5858dd42a2e158f217a1e820f..538589c97580b87aa239ab04a0ea27b7bb04c0fc 100644 (file)
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -258,7 +258,8 @@ void clockevents_notify(unsigned long reason, void *arg)
                cpu = *((int *)arg);
                list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) {
                        if (cpumask_test_cpu(cpu, dev->cpumask) &&
-                           cpumask_weight(dev->cpumask) == 1) {
+                           cpumask_weight(dev->cpumask) == 1 &&
+                           !tick_is_broadcast_device(dev)) {
                                BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
                                list_del(&dev->list);
                        }