After upgrading from 3.7-rc8 to 3.7, I can no longer plug in the power supply to my laptop and not freeze everything. Downgrading to 3.7-rc8 fixes the problem. Steps to reproduce: 1) Install linux 3.7 2) Unplug power supply if connected 3) Plug power supply back in Results: Computer becomes wholly unresponsive. Expected results: Computer should continue working fine. Build date and platform: Build Date : Tue 11 Dec 2012 12:30:56 AM CST Platform : Arch Linux Additional Information: I ran a git bisect from 3.7-rc8 to 3.7, and this seems to be the offending commit: 8d4516904b39507458bee8115793528e12b1d8dd is the first bad commit commit 8d4516904b39507458bee8115793528e12b1d8dd Author: Thomas Gleixner <tglx@linutronix.de> Date: Tue Dec 4 18:59:34 2012 +0100 watchdog: Fix CPU hotplug regression Norbert reported: "3.7-rc6 booted with nmi_watchdog=0 fails to suspend to RAM or offline CPUs. It's reproducable with a KVM guest and physical system." The reason is that commit bcd951cf(watchdog: Use hotplug thread infrastructure) missed to take this into account. So the cpu offline code gets stuck in the teardown function because it accesses non initialized data structures. Add a check for watchdog_enabled into that path to cure the issue. Reported-and-tested-by: Norbert Warmuth <nwarmuth@t-online.de> Tested-by: Joseph Salisbury <joseph.salisbury@canonical.com> Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1211231033230.2701@ionos Link: http://bugs.launchpad.net/bugs/1079534 Signed-off-by: Thomas Gleixner <tglx@linutronix.de> :040000 040000 32962c88d16bc0cf841e114b181163c9450dabde dc9ba81b3cf7a8b40f739855dd9c1a08aaa2fbc5 M kernel Thank you, William Giokas
I see this too on my Lenovo X220. Probably bug #51721 is a duplicate of this bug.
*** Bug 51721 has been marked as a duplicate of this bug. ***
https://lkml.org/lkml/2012/12/14/65 There seems to be someone else that found the same commit as I did.
Makes sense - I'm running laptop mode.
Confirmed: echo 0 > /proc/sys/kernel/nmi_watchdog echo 1 > /proc/sys/kernel/nmi_watchdog results in a kernel panic and disabling laptop-mode-tools works for now.
So if it understand it correctly, this is not yet fixed in Linus' master tree - which means that it is not yet in the upcoming release Linux 3.7.1. I think the patch posted by Bjørn Mork looks reasonable, thought: > https://lkml.org/lkml/2012/12/14/146
Confirm the same problem on my machine
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commit;h=3935e89505a1c3ab3f3b0c7ef0eae54124f48905 Seems to have been reverted.
I can conform this bug on two Lenovo machines (U160 + e330) trying the latest kernel v3.7.1. The machines freeze also when they are in standby mode I plug in the power supply and wake them up.
confirmed on my laptop (Dell Latitude E6420), running kernel 3.7.0-7-generic
Created attachment 90661 [details] 3.8-rc1 patch backported to 3.7 try this 3.8-rc1 pach in your 3.7.* kernel it is marked for .stable, but doesn't appear in 3.7-stable yet.
Bug still exists in 3.7.2.
3.7.3 is now released with the fix for this bug, and everybody should be happy. Enjoy!
closed 3.7.3 tree: commit b791ca8fdc546678386a98a17be6f872472f50a4 Author: Bjørn Mork <bjorn@mork.no> Date: Wed Dec 19 20:51:31 2012 +0100 watchdog: Fix disable/enable regression commit 3935e89505a1c3ab3f3b0c7ef0eae54124f48905 upstream. Commit 8d4516904b39 ("watchdog: Fix CPU hotplug regression") causes an oops or hard lockup when doing