[PATCH 1/5] sched: Enable might_sleep before initializing drivers.

[John Stultz <john.stultz@linaro.org>]

From: Arve Hjønnevåg <arve@android.com>

This allows detection of init bugs in built-in drivers.

CC: Ingo Molnar <mingo@elte.hu>
CC: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 kernel/sched.c |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index aa14a56..0b58415 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -8104,13 +8104,24 @@ static inline int preempt_count_equals(int preempt_offset)
 	return (nested == PREEMPT_INATOMIC_BASE + preempt_offset);
 }
 
+static int __might_sleep_init_called;
+int __init __might_sleep_init(void)
+{
+	__might_sleep_init_called = 1;
+	return 0;
+}
+early_initcall(__might_sleep_init);
+
 void __might_sleep(const char *file, int line, int preempt_offset)
 {
 #ifdef in_atomic
 	static unsigned long prev_jiffy;	/* ratelimiting */
 
 	if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
-	    system_state != SYSTEM_RUNNING || oops_in_progress)
+	    oops_in_progress)
+		return;
+	if (system_state != SYSTEM_RUNNING &&
+	    (!__might_sleep_init_called || system_state != SYSTEM_BOOTING))
 		return;
 	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
 		return;
-- 
1.7.3.2.146.gca209