cpuidle: Fix panic in CPU off-lining with no idle driver

Fix a NULL pointer dereference panic in cpuidle_play_dead() during CPU off-lining when no cpuidle driver is registered. A cpuidle driver may be registered at boot-time based on CPU type. This patch allows an off-lined CPU to enter HLT-based idle in this condition. Signed-off-by: Toshi Kani <[email protected]> Cc: Boris Ostrovsky <[email protected]> Reviewed-by: Srivatsa S. Bhat <[email protected]> Tested-by: Srivatsa S. Bhat <[email protected]> Signed-off-by: Len Brown <[email protected]>
adn770 · Apr 6, 2012 · ee01e66 · ee01e66
1 parent 54f7007
commit ee01e66
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
@@ -74,7 +74,7 @@ static cpuidle_enter_t cpuidle_enter_ops;
 /**
  * cpuidle_play_dead - cpu off-lining
  *
- * Only returns in case of an error
+ * Returns in case of an error or no driver
  */
 int cpuidle_play_dead(void)
 {
@@ -83,6 +83,9 @@ int cpuidle_play_dead(void)
 	int i, dead_state = -1;
 	int power_usage = -1;
 
+	if (!drv)
+		return -ENODEV;
+
 	/* Find lowest-power state that supports long-term idle */
 	for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
 		struct cpuidle_state *s = &drv->states[i];