From 72fcde966252abd17d70e4e216a0411a34523a8f Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 23 May 2007 13:57:30 -0700 Subject: [PATCH] Ignore bogus ACPI info for offline CPUs Booting a SMP kernel with maxcpus=1 on a SMP system leads to a hard hang, because ACPI ignores the maxcpus setting and sends timer broadcast info for the offline CPUs. This results in a stuck for ever call to smp_call_function_single() on an offline CPU. Ignore the bogus information and print a kernel error to remind ACPI folks to fix it. Signed-off-by: Thomas Gleixner Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/time/tick-broadcast.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index eadfce2..8001d37 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -243,11 +243,18 @@ void tick_broadcast_on_off(unsigned long reason, int *oncpu) { int cpu = get_cpu(); - if (cpu == *oncpu) - tick_do_broadcast_on_off(&reason); - else - smp_call_function_single(*oncpu, tick_do_broadcast_on_off, - &reason, 1, 1); + if (!cpu_isset(*oncpu, cpu_online_map)) { + printk(KERN_ERR "tick-braodcast: ignoring broadcast for " + "offline CPU #%d\n", *oncpu); + } else { + + if (cpu == *oncpu) + tick_do_broadcast_on_off(&reason); + else + smp_call_function_single(*oncpu, + tick_do_broadcast_on_off, + &reason, 1, 1); + } put_cpu(); } -- 2.7.4