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

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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 <toshi.kani@hp.com>
Cc: Boris Ostrovsky <boris.ostrovsky@amd.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Tested-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Toshi Kani 2012-03-31 21:37:02 -06:00 committed by Len Brown
parent 54f7007776
commit ee01e66337
1 changed files with 4 additions and 1 deletions
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5
drivers/cpuidle/cpuidle.c
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@ -74,7 +74,7 @@ static cpuidle_enter_t cpuidle_enter_ops;
/** /**
* cpuidle_play_dead - cpu off-lining * 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) int cpuidle_play_dead(void)
{ {
@ -83,6 +83,9 @@ int cpuidle_play_dead(void)
int i, dead_state = -1; int i, dead_state = -1;
int power_usage = -1; int power_usage = -1;
if (!drv)
return -ENODEV;
/* Find lowest-power state that supports long-term idle */ /* Find lowest-power state that supports long-term idle */
for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) { for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
struct cpuidle_state *s = &drv->states[i]; struct cpuidle_state *s = &drv->states[i];