From 07dccf3344010f9b9df7fe725da7e73bca2992df Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Fri, 29 Sep 2006 02:00:22 -0700 Subject: [PATCH] [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 Signed-off-by: Akinobu Mita Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sched.c | 4 +++- kernel/softirq.c | 4 +++- kernel/softlockup.c | 3 ++- kernel/timer.c | 4 +++- 4 files changed, 11 insertions(+), 4 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 5c848fd4e46..b946209d9c1 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5272,9 +5272,11 @@ static struct notifier_block __cpuinitdata migration_notifier = { 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); diff --git a/kernel/softirq.c b/kernel/softirq.c index 3789ca98197..bf25015dce1 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -612,7 +612,9 @@ static struct notifier_block __cpuinitdata cpu_nfb = { __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; diff --git a/kernel/softlockup.c b/kernel/softlockup.c index 03e6a2b0b78..50afeb81330 100644 --- a/kernel/softlockup.c +++ b/kernel/softlockup.c @@ -149,8 +149,9 @@ static struct notifier_block __cpuinitdata cpu_nfb = { __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); diff --git a/kernel/timer.c b/kernel/timer.c index d644f4e9ca0..a2cb1ecb1b2 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -1694,8 +1694,10 @@ static struct notifier_block __cpuinitdata timers_nb = { 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); }