sched: panic on corrupted stack end

Until now, hitting this BUG_ON caused a recursive oops (because oops handling involves do_exit(), which calls into the scheduler, which in turn raises an oops), which caused stuff below the stack to be overwritten until a panic happened (e.g. via an oops in interrupt context, caused by the overwritten CPU index in the thread_info). Just panic directly. Signed-off-by: Jann Horn <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
oohal · Jun 10, 2016 · 29d6455 · 29d6455
1 parent 2f36db7
commit 29d6455
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
@@ -3047,7 +3047,8 @@ static noinline void __schedule_bug(struct task_struct *prev)
 static inline void schedule_debug(struct task_struct *prev)
 {
 #ifdef CONFIG_SCHED_STACK_END_CHECK
-	BUG_ON(task_stack_end_corrupted(prev));
+	if (task_stack_end_corrupted(prev))
+		panic("corrupted stack end detected inside scheduler\n");
 #endif
 
 	if (unlikely(in_atomic_preempt_off())) {