[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: Akinobu Mita <mita@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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4 changed files with 11 additions and 4 deletions
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@ -5272,9 +5272,11 @@ static struct notifier_block __cpuinitdata migration_notifier = {
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int __init migration_init(void)
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{
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void *cpu = (void *)(long)smp_processor_id();
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int err;
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/* Start one for the boot CPU: */
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migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
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err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
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BUG_ON(err == NOTIFY_BAD);
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migration_call(&migration_notifier, CPU_ONLINE, cpu);
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register_cpu_notifier(&migration_notifier);
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@ -612,7 +612,9 @@ static struct notifier_block __cpuinitdata cpu_nfb = {
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__init int spawn_ksoftirqd(void)
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{
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void *cpu = (void *)(long)smp_processor_id();
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cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
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int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
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BUG_ON(err == NOTIFY_BAD);
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cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
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register_cpu_notifier(&cpu_nfb);
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return 0;
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@ -149,8 +149,9 @@ static struct notifier_block __cpuinitdata cpu_nfb = {
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__init void spawn_softlockup_task(void)
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{
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void *cpu = (void *)(long)smp_processor_id();
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int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
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cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
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BUG_ON(err == NOTIFY_BAD);
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cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
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register_cpu_notifier(&cpu_nfb);
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@ -1694,8 +1694,10 @@ static struct notifier_block __cpuinitdata timers_nb = {
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void __init init_timers(void)
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{
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timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
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int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
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(void *)(long)smp_processor_id());
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BUG_ON(err == NOTIFY_BAD);
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register_cpu_notifier(&timers_nb);
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open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
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}
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