[PATCH] check return value of cpu_callback

Spawing ksoftirqd, migration, or watchdog, and calling init_timers_cpu() may fail with small memory. If it happens in initcalls, kernel NULL pointer dereference happens later. This patch makes crash happen immediately in such cases. It seems a bit better than getting kernel NULL pointer dereference later.

Akinobu Mita committed 20 years ago

Commit 07dccf31 parent 6c2d8b54 files · +11 −4Browse files

Unified · Split

4 files

kernel/sched.c +3 −1
kernel/softirq.c +3 −1
kernel/softlockup.c +2 −1
kernel/timer.c +3 −1

kernel/sched.c+3−1

@@ -5272,9 +5272,11 @@ static struct notifier_block __cpuinitdata migration_notifier = { · 5271 unmodified lines
5272	5272	int __init migration_init(void)
5273	5273	{
5274	5274	void cpu = (void )(long)smp_processor_id();
	5275	+ int err;
5275	5276
5276	5277	/* Start one for the boot CPU: */
5277		− migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
	5278	+ err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
	5279	+ BUG_ON(err == NOTIFY_BAD);
5278	5280	migration_call(&migration_notifier, CPU_ONLINE, cpu);
5279	5281	register_cpu_notifier(&migration_notifier);
5280	5282

kernel/softirq.c+3−1

@@ -612,7 +612,9 @@ static struct notifier_block __cpuinitdata cpu_nfb = { · 611 unmodified lines
612	612	__init int spawn_ksoftirqd(void)
613	613	{
614	614	void cpu = (void )(long)smp_processor_id();
615		− cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
	615	+ int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
	616	+
	617	+ BUG_ON(err == NOTIFY_BAD);
616	618	cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
617	619	register_cpu_notifier(&cpu_nfb);
618	620	return 0;

kernel/softlockup.c+2−1

@@ -149,8 +149,9 @@ static struct notifier_block __cpuinitdata cpu_nfb = { · 148 unmodified lines
149	149	__init void spawn_softlockup_task(void)
150	150	{
151	151	void cpu = (void )(long)smp_processor_id();
	152	+ int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
152	153
153		− cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
	154	+ BUG_ON(err == NOTIFY_BAD);
154	155	cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
155	156	register_cpu_notifier(&cpu_nfb);
156	157

kernel/timer.c+3−1

@@ -1694,8 +1694,10 @@ static struct notifier_block __cpuinitdata timers_nb = { · 1693 unmodified lines
1694	1694
1695	1695	void __init init_timers(void)
1696	1696	{
1697		− timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
	1697	+ int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
1698	1698	(void *)(long)smp_processor_id());
	1699	+
	1700	+ BUG_ON(err == NOTIFY_BAD);
1699	1701	register_cpu_notifier(&timers_nb);
1700	1702	open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
1701	1703	}