Commit 82ed6f7e authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

timers: Replace BUG_ON()s 



The timer code still has a few BUG_ON()s left which are crashing the kernel
in situations where it still can recover or simply refuse to take an
action.

Remove the one in the hotplug callback which checks for the CPU being
offline. If that happens then the whole hotplug machinery will explode in
colourful ways.

Replace the rest with WARN_ON_ONCE() and conditional returns where
appropriate.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarGuenter Roeck <linux@roeck-us.net>
Reviewed-by: default avatarJacob Keller <jacob.e.keller@intel.com>
Reviewed-by: default avatarAnna-Maria Behnsen <anna-maria@linutronix.de>
Link: https://lore.kernel.org/r/20221123201624.769128888@linutronix.de
parent 9a5a3056

kernel/time/timer.c

+6 −5
Original line number Diff line number Diff line
@@ -1193,7 +1193,8 @@ EXPORT_SYMBOL(timer_reduce); 
 */

void add_timer(struct timer_list *timer)

{

	BUG_ON(timer_pending(timer));

	if (WARN_ON_ONCE(timer_pending(timer)))

		return;

	__mod_timer(timer, timer->expires, MOD_TIMER_NOTPENDING);

}

EXPORT_SYMBOL(add_timer);
@@ -1210,7 +1211,8 @@ void add_timer_on(struct timer_list *timer, int cpu) 
	struct timer_base *new_base, *base;

	unsigned long flags;



	BUG_ON(timer_pending(timer) || !timer->function);

	if (WARN_ON_ONCE(timer_pending(timer) || !timer->function))

		return;



	new_base = get_timer_cpu_base(timer->flags, cpu);
@@ -2017,8 +2019,6 @@ int timers_dead_cpu(unsigned int cpu) 
	struct timer_base *new_base;

	int b, i;



	BUG_ON(cpu_online(cpu));



	for (b = 0; b < NR_BASES; b++) {

		old_base = per_cpu_ptr(&timer_bases[b], cpu);

		new_base = get_cpu_ptr(&timer_bases[b]);
@@ -2035,7 +2035,8 @@ int timers_dead_cpu(unsigned int cpu) 
		 */

		forward_timer_base(new_base);



		BUG_ON(old_base->running_timer);

		WARN_ON_ONCE(old_base->running_timer);

		old_base->running_timer = NULL;



		for (i = 0; i < WHEEL_SIZE; i++)

			migrate_timer_list(new_base, old_base->vectors + i);