From 302745699c1b675b5d2a1af87271de10e4d96b6a Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 22 Sep 2008 19:02:25 +0200 Subject: clockevents: check broadcast device not tick device Impact: Possible hang on CPU online observed on AMD C1E machines. The broadcast setup code looks at the mode of the tick device to determine whether it needs to be shut down or setup. This is wrong when the broadcast mode is set to one shot already. This can happen when a CPU is brought online as it goes through the periodic setup first. The problem went unnoticed as sane systems do not call into that code before the switch to one shot for the clock event device happens. The AMD C1E idle routine switches over immediately and thereby shuts down the just setup device before the first interrupt happens. Signed-off-by: Thomas Gleixner --- kernel/time/tick-broadcast.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index f1f3eee2811..e2b66d1c8ca 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -235,7 +235,7 @@ static void tick_do_broadcast_on_off(void *why) case CLOCK_EVT_NOTIFY_BROADCAST_FORCE: if (!cpu_isset(cpu, tick_broadcast_mask)) { cpu_set(cpu, tick_broadcast_mask); - if (td->mode == TICKDEV_MODE_PERIODIC) + if (bc->mode == TICKDEV_MODE_PERIODIC) clockevents_shutdown(dev); } if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE) @@ -245,7 +245,7 @@ static void tick_do_broadcast_on_off(void *why) if (!tick_broadcast_force && cpu_isset(cpu, tick_broadcast_mask)) { cpu_clear(cpu, tick_broadcast_mask); - if (td->mode == TICKDEV_MODE_PERIODIC) + if (bc->mode == TICKDEV_MODE_PERIODIC) tick_setup_periodic(dev, 0); } break; -- cgit v1.2.3