* [PATCH V2] cpuidle: check dev before usage in cpuidle_use_deepest_state
@ 2017-04-27 1:47 Li, Fei
2017-04-27 9:39 ` Andy Shevchenko
0 siblings, 1 reply; 2+ messages in thread
From: Li, Fei @ 2017-04-27 1:47 UTC (permalink / raw)
To: Shi, FengX, rjw, daniel.lezcano
Cc: linux-pm, linux-kernel, Koul, Vinod, Shevchenko, Andriy
In case of there is no cpuidle devices registered, dev will be null, and
panic will be triggered like below;
In this patch, add checking of dev before usage, like that done in
cpuidle_idle_call.
Panic without fix:
[ 184.961328] BUG: unable to handle kernel NULL pointer dereference at
(null)
[ 184.961328] IP: cpuidle_use_deepest_state+0x30/0x60
...
[ 184.961328] play_idle+0x8d/0x210
[ 184.961328] ? __schedule+0x359/0x8e0
[ 184.961328] ? _raw_spin_unlock_irqrestore+0x28/0x50
[ 184.961328] ? kthread_queue_delayed_work+0x41/0x80
[ 184.961328] clamp_idle_injection_func+0x64/0x1e0
Fixes: bb8313b603eb8 ("cpuidle: Allow enforcing deepest idle state selection")
Signed-off-by: Li, Fei <fei.li@intel.com>
Tested-by: Shi, Feng <fengx.shi@intel.com>
---
drivers/cpuidle/cpuidle.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 548b90b..2706be7 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -111,7 +111,8 @@ void cpuidle_use_deepest_state(bool enable)
preempt_disable();
dev = cpuidle_get_device();
- dev->use_deepest_state = enable;
+ if (dev)
+ dev->use_deepest_state = enable;
preempt_enable();
}
--
1.9.1
Best Regards,
Fei
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH V2] cpuidle: check dev before usage in cpuidle_use_deepest_state
2017-04-27 1:47 [PATCH V2] cpuidle: check dev before usage in cpuidle_use_deepest_state Li, Fei
@ 2017-04-27 9:39 ` Andy Shevchenko
0 siblings, 0 replies; 2+ messages in thread
From: Andy Shevchenko @ 2017-04-27 9:39 UTC (permalink / raw)
To: Li, Fei, Shi, FengX, rjw, daniel.lezcano
Cc: linux-pm, linux-kernel, Koul, Vinod
On Thu, 2017-04-27 at 01:47 +0000, Li, Fei wrote:
> In case of there is no cpuidle devices registered, dev will be null,
> and
> panic will be triggered like below;
> In this patch, add checking of dev before usage, like that done in
> cpuidle_idle_call.
>
> Panic without fix:
> [ 184.961328] BUG: unable to handle kernel NULL pointer dereference
> at
> (null)
> [ 184.961328] IP: cpuidle_use_deepest_state+0x30/0x60
> ...
> [ 184.961328] play_idle+0x8d/0x210
> [ 184.961328] ? __schedule+0x359/0x8e0
> [ 184.961328] ? _raw_spin_unlock_irqrestore+0x28/0x50
> [ 184.961328] ? kthread_queue_delayed_work+0x41/0x80
> [ 184.961328] clamp_idle_injection_func+0x64/0x1e0
FWIW:
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
P.S. V2 is mistakenly left from internal review AFAIU.
>
> Fixes: bb8313b603eb8 ("cpuidle: Allow enforcing deepest idle state
> selection")
> Signed-off-by: Li, Fei <fei.li@intel.com>
> Tested-by: Shi, Feng <fengx.shi@intel.com>
> ---
> drivers/cpuidle/cpuidle.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index 548b90b..2706be7 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -111,7 +111,8 @@ void cpuidle_use_deepest_state(bool enable)
>
> preempt_disable();
> dev = cpuidle_get_device();
> - dev->use_deepest_state = enable;
> + if (dev)
> + dev->use_deepest_state = enable;
> preempt_enable();
> }
>
--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
^ permalink raw reply [flat|nested] 2+ messages in thread
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