[PATCH] x86/mce: timer must be setup unconditionally

[Jan Beulich]

mce_timer must be passed to setup_timer() in all cases, no matter
whether it is going to be actually used. Otherwise, when the CPU gets
brought down, its call to del_timer_sync() will never return, as the
timer won't have a base associated, and hence lock_timer_base() will
loop infinitely.

(Patch applying to -tip is attached.)

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>

---
 arch/x86/kernel/cpu/mcheck/mce.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- linux-2.6.32-rc8/arch/x86/kernel/cpu/mcheck/mce.c
+++ 2.6.32-rc8-x86-mce-setup-timer-always/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1374,13 +1374,14 @@ static void mce_init_timer(void)
 	struct timer_list *t = &__get_cpu_var(mce_timer);
 	int *n = &__get_cpu_var(mce_next_interval);
 
+	setup_timer(t, mcheck_timer, smp_processor_id());
+
 	if (mce_ignore_ce)
 		return;
 
 	*n = check_interval * HZ;
 	if (!*n)
 		return;
-	setup_timer(t, mcheck_timer, smp_processor_id());
 	t->expires = round_jiffies(jiffies + *n);
 	add_timer_on(t, smp_processor_id());
 }



mce_timer must be passed to setup_timer() in all cases, no matter
whether it is going to be actually used. Otherwise, when the CPU gets
brought down, its call to del_timer_sync() will never return, as the
timer won't have a base associated, and hence lock_timer_base() will
loop infinitely.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>

---
 arch/x86/kernel/cpu/mcheck/mce.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1388,13 +1388,14 @@ static void __mcheck_cpu_init_timer(
 	struct timer_list *t = &__get_cpu_var(mce_timer);
 	int *n = &__get_cpu_var(mce_next_interval);
 
+	setup_timer(t, mce_start_timer, smp_processor_id());
+
 	if (mce_ignore_ce)
 		return;
 
 	*n = check_interval * HZ;
 	if (!*n)
 		return;
-	setup_timer(t, mce_start_timer, smp_processor_id());
 	t->expires = round_jiffies(jiffies + *n);
 	add_timer_on(t, smp_processor_id());
 }