Eric Lee / linux-smarc-t335x-v3.2

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Commit 07dccf3344010f9b9df7fe725da7e73bca2992df

Authored by Akinobu Mita
Committed by Linus Torvalds
1 parent 6c2d8b5dca
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

[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>

Showing 4 changed files with 11 additions and 4 deletions Side-by-side Diff

... ... @@ -5272,9 +5272,11 @@
5272 5272 int __init migration_init(void)
5273 5273 {
5274 5274 void *cpu = (void *)(long)smp_processor_id();
  5275 + int err;
5275 5276  
5276 5277 /* Start one for the boot CPU: */
5277   - migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
  5278 + err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
  5279 + BUG_ON(err == NOTIFY_BAD);
5278 5280 migration_call(&migration_notifier, CPU_ONLINE, cpu);
5279 5281 register_cpu_notifier(&migration_notifier);
5280 5282  
... ... @@ -612,7 +612,9 @@
612 612 __init int spawn_ksoftirqd(void)
613 613 {
614 614 void *cpu = (void *)(long)smp_processor_id();
615   - cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
  615 + int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
  616 +
  617 + BUG_ON(err == NOTIFY_BAD);
616 618 cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
617 619 register_cpu_notifier(&cpu_nfb);
618 620 return 0;
... ... @@ -149,8 +149,9 @@
149 149 __init void spawn_softlockup_task(void)
150 150 {
151 151 void *cpu = (void *)(long)smp_processor_id();
  152 + int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
152 153  
153   - cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
  154 + BUG_ON(err == NOTIFY_BAD);
154 155 cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
155 156 register_cpu_notifier(&cpu_nfb);
156 157  
... ... @@ -1694,8 +1694,10 @@
1694 1694  
1695 1695 void __init init_timers(void)
1696 1696 {
1697   - timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
  1697 + int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
1698 1698 (void *)(long)smp_processor_id());
  1699 +
  1700 + BUG_ON(err == NOTIFY_BAD);
1699 1701 register_cpu_notifier(&timers_nb);
1700 1702 open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
1701 1703 }