Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | 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 |
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4.11-stable review patch. If anyone has any objections, please let me know.
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From: Li, Fei <fei.li@intel.com>
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 <fei.li@intel.com> Tested-by: Shi, Feng <fengx.shi@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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(); }
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