[PATCH] check return value of cpu_callback
- From: Akinobu Mita <mita@xxxxxxxxxxxxxxxx>
- Date: Sun, 13 Aug 2006 18:18:10 +0800
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@xxxxxxx>
Signed-off-by: Akinobu Mita <mita@xxxxxxxxxxxxxxxx>
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);
}
-
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