Bug 71961

Summary:	panic occured shortly after resume
Product:	Drivers	Reporter:	Luc Pi (pionchon.luc)
Component:	network-wireless	Assignee:	drivers_network-wireless (drivers_network-wireless)
Status:	NEEDINFO ---
Severity:	normal	CC:	tianyu.lan
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	3.14.0-031400rc6	Subsystem:
Regression:	Yes	Bisected commit-id:
Attachments:	photo of the panic screen kernel panic console screen

Description Luc Pi 2014-03-12 12:18:40 UTC

Created attachment 129161 [details]
photo of the panic screen

I suspended my laptop (MacBook 2,1) by closing the lid. Shortly after I reopened my laptop and the system resumed, it switched to a console with a "panic occured" message. Then the keyboard does not answer anymore (I could not switch to another console nor to X.org).

I join a photo of the panic screen. I am sorry for the low quality of the photo. I hope that you can read valuable information anyway. Or is there a log where we can read the information afterward?

I am testing this new kernel from [1] to see if it resolves bug [2]: "sometimes suspend fails and the whole system freeze with high CPU usage"

[1] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.14-rc6-trusty
[2] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1289972

Comment 1 Lan Tianyu 2014-03-12 12:45:35 UTC

Please follow this file to debug.
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/power/basic-pm-debugging.txt

From the log, the panic seems happens in the wireless driver. Please unload the wireless driver and try again.

Comment 2 Luc Pi 2014-03-12 21:47:23 UTC

Thanks for your quick answer!

The instructions you gave are a bit complicated to me.

What I did:
1. 'rmmod ath9k' (I guess this is my wireless driver)
2. 5 suspend/resume cycles by closing my laptop's lid
3. 'cat /sys/kernel/debug/suspend_stats'
   success: 5
   fail: 0
4. 'lsmod ath9k'
5. 5 suspend/resume cycles by closing my laptop's lid
6. 'cat /sys/kernel/debug/suspend_stats'
   success: 10
   fail: 0

The panic did not reproduce. Shall I test it more times? With my normal usage, I suspend/resume my laptop about 5-10 times a day. I'll keep watching in the coming days if it reproduce with the driver loaded. However it is not very practical for me to use my laptop without the wireless.


NOTE: Sometimes the laptop resumes on a black screen. The mouse pointer reacts, and it changes when I move it around, as it hovers content, but the screen is black. I need to switch to a console then back to X (Ctrl-Alt-F3, Ctrl-Alt-F7) to completely resume the session.

Comment 3 Lan Tianyu 2014-03-14 03:23:02 UTC

(In reply to Luc Pionchon from comment #2)
 > The panic did not reproduce. Shall I test it more times? With my normal
> usage, I suspend/resume my laptop about 5-10 times a day. I'll keep watching
> in the coming days if it reproduce with the driver loaded. However it is not
> very practical for me to use my laptop without the wireless.

From current logs, this is wireless bug and so reassign.

Comment 4 Luc Pi 2014-03-15 20:42:23 UTC

Now I am at 27 resume successes, with the wireless module loaded, and the panic did not reappear.

$ cat /sys/kernel/debug/suspend_stats
success: 27
fail: 0

Comment 5 Luc Pi 2014-04-09 18:29:03 UTC

I just got the kernel panic again.

Comment 6 Luc Pi 2014-04-09 18:30:17 UTC

Created attachment 131801 [details]
kernel panic console screen

This time I got a much more readable screen shot