[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 <mingo@elte.hu>
Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index 03e6a2b..50afeb8 100644
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -149,8 +149,9 @@
__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);
