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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.

Akinobu Mita committed 20 years ago

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

Unified · Split

4 files
  1. kernel/sched.c +3 −1
  2. kernel/softirq.c +3 −1
  3. kernel/softlockup.c +2 −1
  4. kernel/timer.c +3 −1
kernel/sched.c+3−1
@@ -5272,9 +5272,11 @@ static struct notifier_block __cpuinitdata migration_notifier = { · 5271 unmodified lines
5272int __init migration_init(void)5272int __init migration_init(void)
5273{5273{
5274 void *cpu = (void *)(long)smp_processor_id();5274 void *cpu = (void *)(long)smp_processor_id();
5275 int err;
5275 5276
5276 /* Start one for the boot CPU: */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 migration_call(&migration_notifier, CPU_ONLINE, cpu);5280 migration_call(&migration_notifier, CPU_ONLINE, cpu);
5279 register_cpu_notifier(&migration_notifier);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__init int spawn_ksoftirqd(void)612__init int spawn_ksoftirqd(void)
613{613{
614 void *cpu = (void *)(long)smp_processor_id();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 cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);618 cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
617 register_cpu_notifier(&cpu_nfb);619 register_cpu_notifier(&cpu_nfb);
618 return 0;620 return 0;
kernel/softlockup.c+2−1
@@ -149,8 +149,9 @@ static struct notifier_block __cpuinitdata cpu_nfb = { · 148 unmodified lines
149__init void spawn_softlockup_task(void)149__init void spawn_softlockup_task(void)
150{150{
151 void *cpu = (void *)(long)smp_processor_id();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 cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);155 cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
155 register_cpu_notifier(&cpu_nfb);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
1695void __init init_timers(void)1695void __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 (void *)(long)smp_processor_id());1698 (void *)(long)smp_processor_id());
1699
1700 BUG_ON(err == NOTIFY_BAD);
1699 register_cpu_notifier(&timers_nb);1701 register_cpu_notifier(&timers_nb);
1700 open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);1702 open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
1701}1703}