The patch titled
check return value of cpu_callback
has been added to the -mm tree. Its filename is
check-return-value-of-cpu_callback.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: check return value of cpu_callback
From: Akinobu Mita <mita@xxxxxxxxxxxxxxxx>
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>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/sched.c | 4 +++-
kernel/softirq.c | 4 +++-
kernel/softlockup.c | 3 ++-
kernel/timer.c | 4 +++-
4 files changed, 11 insertions(+), 4 deletions(-)
diff -puN kernel/sched.c~check-return-value-of-cpu_callback kernel/sched.c
--- a/kernel/sched.c~check-return-value-of-cpu_callback
+++ a/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);
diff -puN kernel/softirq.c~check-return-value-of-cpu_callback kernel/softirq.c
--- a/kernel/softirq.c~check-return-value-of-cpu_callback
+++ a/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;
diff -puN kernel/softlockup.c~check-return-value-of-cpu_callback kernel/softlockup.c
--- a/kernel/softlockup.c~check-return-value-of-cpu_callback
+++ a/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);
diff -puN kernel/timer.c~check-return-value-of-cpu_callback kernel/timer.c
--- a/kernel/timer.c~check-return-value-of-cpu_callback
+++ a/kernel/timer.c
@@ -1688,8 +1688,10 @@ 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);
}
_
Patches currently in -mm which might be from mita@xxxxxxxxxxxxxxxx are
check-return-value-of-cpu_callback.patch
-
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