Messages in this thread | | | Date | Mon, 18 Nov 2013 10:45:23 -0700 | From | Shuah Khan <> | Subject | Re: [PATCH] power: Change device_wakeup_enable() to check for null dev_name(dev) |
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On 11/15/2013 05:32 PM, Rafael J. Wysocki wrote: > On Friday, November 15, 2013 05:16:31 PM Shuah Khan wrote: >> On 11/15/2013 05:21 PM, Rafael J. Wysocki wrote: >>> On Friday, November 15, 2013 05:03:57 PM Shuah Khan wrote: >>>> device_wakeup_enable() uses dev_name(dev) as the wakeup source name. >>>> When it gets called with a device with its name not yet set, ws structure >>>> with ws->name = NULL gets created. >>>> >>>> When kernel is booted with wakeup_source_activate enabled, it will panic >>>> when the trace point code tries to derefernces ws->name. >>>> >>>> Change device_wakeup_enable() to check for dev_name(dev) null condition >>>> and return -EINVAL to avoid panics when device_wakeup_enable() gets called >>>> before device is fully initialized with its name. >> return -EINVAL; >>> >>> Can you please use WARN_ON(!dev_name(dev)) here? While I agree that it is a >>> bad idea to crash the kernel because dev has no name, that indicates a driver >>> bug that shouldn't be too easy to ignore. >>> >>> Thanks! >>> >> >> Right. ok I will re-cut the patch with WARN_ON and send it. fyi I did >> send fix for the driver (power_supply) as well. >> >> http://www.kernelhub.org/?msg=362354&p=2 > > That's OK (thanks for taking care of this), but there may be more brilliant > stuff like that in the future and people should see right away that something's > wrong in those cases. >
Rafael/Anton/David,
I added WARN_ON and testing the patch. We have two instance of device_wakeup_enable() calls with null dev_name during boot. Both are from power_supply_register(). One when AC Adapter [ADP1] is added and the second when device: 'BAT1' gets added.
[ 4.412959] device_wakeup_enable() called with null device nme [ 4.412967] device: 'ADP1': device_add
[ 4.460190] device_wakeup_enable() called with null device nme [ 4.460197] device: 'BAT1': device_add
I think adding WARN_ON to device_wakeup_enable() and fix to power_supply_register() should go in as a dependent patch series, to avoid panics during boot. As soon as the device_wakeup_enable() WARN_ON goes in, I suspect most laptops will panic during boot, similar to what I am seeing in my testing. Thoughts?
I will send these fixes, maybe these two can be funneled through PM tree with power_supply maintainers ACK for the power_supply_register() fix.
thanks, -- Shuah
-- Shuah Khan Senior Linux Kernel Developer - Open Source Group Samsung Research America(Silicon Valley) shuah.kh@samsung.com | (970) 672-0658
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