From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Li, Fei" , "Shi, Feng" , Andy Shevchenko , "Rafael J. Wysocki" Subject: [PATCH 4.11 158/197] cpuidle: check dev before usage in cpuidle_use_deepest_state() Date: Tue, 23 May 2017 22:08:39 +0200 Message-Id: <20170523200837.405173957@linuxfoundation.org> In-Reply-To: <20170523200821.666872592@linuxfoundation.org> References: <20170523200821.666872592@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Li, Fei commit 41dc750ea67f317c0deedde713d1728425524ef2 upstream. 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 Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/cpuidle/cpuidle.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -111,7 +111,8 @@ void cpuidle_use_deepest_state(bool enab preempt_disable(); dev = cpuidle_get_device(); - dev->use_deepest_state = enable; + if (dev) + dev->use_deepest_state = enable; preempt_enable(); }