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 <[email protected]> P.S. V2 is mistakenly left from internal review AFAIU. > > Fixes: bb8313b603eb8 ("cpuidle: Allow enforcing deepest idle state > selection") > Signed-off-by: Li, Fei <[email protected]> > Tested-by: Shi, Feng <[email protected]> > --- > 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 <[email protected]> Intel Finland Oy
