[dm-devel] Soft lockup during suspend since ~2.6.36 [bisected]

[Thilo-Alexander Ginkel]

On Tue, Apr 26, 2011 at 15:11, Tejun Heo <tj at kernel.org> wrote:
> Hello, sorry about the delay.  Was on the road and then sick.

No problem. Thanks for getting back to me.

>> In the meantime I also figured out that 2.6.39-rc3 seems to fix the
>> issue (there have been some work queue changes, so this is somewhat
>> sensible)
>
> Hmmm... that's a big demotivator.  :-)

Well, I get your point. ;-) Maybe this fact can help as a motivator: I
ran some further tests and while -rc3 seems to be ok (and survived 100
suspend/resume cycles), the issue strangely seems to be back with -rc4
(the softlockup call stack that I can see is identical to the photos
below; the lockup happened after only two cycles).

> Before I go ahead and try that, do you happen to have softlockup dump?
> ie. stack traces of the stuck tasks?  I can't find the original
> posting.

Sure:

>From <BANLkTi=n4jLsjOYCd0L3hYb30sgPmdv_WA at mail.gmail.com>:
> Unfortunately, the output via a serial console becomes garbled after
> "Entering mem sleep", so I went for patching dumpstack_64.c and a
> couple of other source files to reduce the verbosity. I hope not to
> have stripped any essential information. The result is available in
> these pictures:
>   https://secure.tgbyte.de/dropbox/IeZalo4t-1.jpg
>   https://secure.tgbyte.de/dropbox/IeZalo4t-2.jpg
>
> For both traces, the printed error message reads: "BUG: soft lockup -
> CPU#3 stuck for 67s! [kblockd:28]"

Thanks,
Thilo