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Commit 07dccf33 authored by Akinobu Mita's avatar Akinobu Mita Committed by Linus Torvalds
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[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.

Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAkinobu Mita <mita@miraclelinux.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 6c2d8b5d

kernel/sched.c

+3 −1
Original line number Original line Diff line number Diff line
@@ -5272,9 +5272,11 @@ static struct notifier_block __cpuinitdata migration_notifier = { 
int __init migration_init(void)

int __init migration_init(void)

{

{

	void *cpu = (void *)(long)smp_processor_id();

	void *cpu = (void *)(long)smp_processor_id();

	int err;





	/* Start one for the boot CPU: */

	/* Start one for the boot CPU: */

	migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);

	err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);

	BUG_ON(err == NOTIFY_BAD);

	migration_call(&migration_notifier, CPU_ONLINE, cpu);

	migration_call(&migration_notifier, CPU_ONLINE, cpu);

	register_cpu_notifier(&migration_notifier);

	register_cpu_notifier(&migration_notifier);

kernel/softirq.c

+3 −1
Original line number Original line Diff line number Diff line
@@ -612,7 +612,9 @@ static struct notifier_block __cpuinitdata cpu_nfb = { 
__init int spawn_ksoftirqd(void)

__init int spawn_ksoftirqd(void)

{

{

	void *cpu = (void *)(long)smp_processor_id();

	void *cpu = (void *)(long)smp_processor_id();

	cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);

	int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);



	BUG_ON(err == NOTIFY_BAD);

	cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);

	cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);

	register_cpu_notifier(&cpu_nfb);

	register_cpu_notifier(&cpu_nfb);

	return 0;

	return 0;

kernel/softlockup.c

+2 −1
Original line number Original line Diff line number Diff line
@@ -149,8 +149,9 @@ static struct notifier_block __cpuinitdata cpu_nfb = { 
__init void spawn_softlockup_task(void)

__init void spawn_softlockup_task(void)

{

{

	void *cpu = (void *)(long)smp_processor_id();

	void *cpu = (void *)(long)smp_processor_id();

	int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);





	cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);

	BUG_ON(err == NOTIFY_BAD);

	cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);

	cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);

	register_cpu_notifier(&cpu_nfb);

	register_cpu_notifier(&cpu_nfb);

kernel/timer.c

+3 −1
Original line number Original line Diff line number Diff line
@@ -1694,8 +1694,10 @@ static struct notifier_block __cpuinitdata timers_nb = { 




void __init init_timers(void)

void __init init_timers(void)

{

{

	timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,

	int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,

				(void *)(long)smp_processor_id());

				(void *)(long)smp_processor_id());



	BUG_ON(err == NOTIFY_BAD);

	register_cpu_notifier(&timers_nb);

	register_cpu_notifier(&timers_nb);

	open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);

	open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);

}

}