From 41dc750ea67f317c0deedde713d1728425524ef2 Mon Sep 17 00:00:00 2001 From: "Li, Fei" Date: Thu, 27 Apr 2017 01:47:25 +0000 Subject: [PATCH] cpuidle: check dev before usage in cpuidle_use_deepest_state() 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 Tested-by: Shi, Feng Reviewed-by: Andy Shevchenko Cc: 4.10+ # 4.10+ Signed-off-by: Rafael J. Wysocki --- 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 548b90be7685..2706be7ed334 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(); } -- 2.20.1