Re: 2.6.29-git13: Reported regressions from 2.6.28

From: Linus Torvalds
Date: Mon Apr 06 2009 - 18:03:34 EST




On Mon, 6 Apr 2009, Rafael J. Wysocki wrote:
>
> Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=13019
> Subject : /proc/<pid>/maps offset output broken in 2.6.29
> Submitter : "Chris Friesen" <cfriesen@xxxxxxxxxx>
> Date : 2009-04-01 23:18 (6 days old)
> References : http://marc.info/?l=linuxppc-embedded&m=123862902916059&w=4
> Handled-By : Hugh Dickins <hugh@xxxxxxxxxxx>

I don't think that's a regression, nor really a bug. It looks cosmetic,
and likely to be fixed, but not really worth worrying about.

> Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=13018
> Subject : 2.6.29 on MacBook 2,1 fails to reboot
> Submitter : Trenton Adams <trenton.d.adams@xxxxxxxxx>
> Date : 2009-03-30 2:04 (8 days old)
> References : http://marc.info/?l=linux-kernel&m=123837870307249&w=4
> Handled-By : "Morten P.D. Stevens" <mstevens@xxxxxxxxxxxxxxxxxxxx>

This went through bisection, but looking at the email log, I tend to
suspect that maybe Trenton marked some versions good even though they
weren't (because they got versions numbers from v2.6.27), and didn't
realize that that messes up bisection in a big way.

The bug _sounds_ like some deadlock due to lock problems - the shutdown
path often triggers locks that no other path really cares about. And we
had some lock problems in the sound subsystem that got fixed post-2.6.28,
for example.

And it looks like the problem is somewhere in sound shutdown:

12181 delete_module("snd_hda_codec", O_RDONLY|O_EXCL) = -1 EAGAIN (Resource temporarily unavailable) <0.000011>

So commits like 91054598f794fb5d8a0b1e747ff8e2e8fc2115b3 ("ALSA: pcm_oss,
fix locking typo") might explain it.

Linus
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