timer: Fix hotplug regression

The recent timer wheel rework removed the get/put_cpu_var() pair in the hotplug migration code, which results in: BUG: using smp_processor_id() in preemptible [00000000] code: hib.sh/2845 ... [<ffffffff810d4fa3>] timer_cpu_notify+0x53/0x12 That hunk is a leftover from an earlier iteration and went unnoticed so far. Restore the previous code which was obviously correct. Fixes: 0eeda71 'timer: Replace timer base by a cpu index' Reported-and_tested-by: Borislav Petkov <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]>
akeromi · Jun 26, 2015 · 24bfcb1 · 24bfcb1
1 parent 56a94f1
commit 24bfcb1
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
@@ -1566,7 +1566,7 @@ static void migrate_timers(int cpu)
 
 	BUG_ON(cpu_online(cpu));
 	old_base = per_cpu_ptr(&tvec_bases, cpu);
-	new_base = this_cpu_ptr(&tvec_bases);
+	new_base = get_cpu_ptr(&tvec_bases);
 	/*
 	 * The caller is globally serialized and nobody else
 	 * takes two locks at once, deadlock is not possible.
@@ -1590,6 +1590,7 @@ static void migrate_timers(int cpu)
 
 	spin_unlock(&old_base->lock);
 	spin_unlock_irq(&new_base->lock);
+	put_cpu_ptr(&tvec_bases);
 }
 
 static int timer_cpu_notify(struct notifier_block *self,