Messages in this thread Patch in this message | | | Date | Sun, 13 Aug 2006 18:18:10 +0800 | From | Akinobu Mita <> | Subject | [PATCH] check return value of cpu_callback |
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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>
kernel/sched.c | 4 +++- kernel/softirq.c | 4 +++- kernel/softlockup.c | 3 ++- kernel/timer.c | 4 +++- 4 files changed, 11 insertions(+), 4 deletions(-)
Index: work-failmalloc/kernel/softirq.c =================================================================== --- work-failmalloc.orig/kernel/softirq.c +++ work-failmalloc/kernel/softirq.c @@ -612,7 +612,9 @@ static struct notifier_block __cpuinitda __init int spawn_ksoftirqd(void) { 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); register_cpu_notifier(&cpu_nfb); return 0; Index: work-failmalloc/kernel/softlockup.c =================================================================== --- work-failmalloc.orig/kernel/softlockup.c +++ work-failmalloc/kernel/softlockup.c @@ -149,8 +149,9 @@ static struct notifier_block __cpuinitda __init void spawn_softlockup_task(void) { 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); register_cpu_notifier(&cpu_nfb); Index: work-failmalloc/kernel/sched.c =================================================================== --- work-failmalloc.orig/kernel/sched.c +++ work-failmalloc/kernel/sched.c @@ -5237,9 +5237,11 @@ static struct notifier_block __cpuinitda int __init migration_init(void) { void *cpu = (void *)(long)smp_processor_id(); + int err; /* 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); register_cpu_notifier(&migration_notifier); Index: work-failmalloc/kernel/timer.c =================================================================== --- work-failmalloc.orig/kernel/timer.c +++ work-failmalloc/kernel/timer.c @@ -1715,8 +1715,10 @@ static struct notifier_block __cpuinitda 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()); + + BUG_ON(err == NOTIFY_BAD); register_cpu_notifier(&timers_nb); open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL); } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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