Re: [1/6] 2.6.21-rc2: known regressions

Re: [1/6] 2.6.21-rc2: known regressions

[Andrew Morton]

On Mon, 5 Mar 2007 02:50:31 +0100 Adrian Bunk <bunk@stusta.de> wrote:

> This email lists some known regressions in 2.6.21-rc2 compared to 2.6.20
> that are not yet fixed in Linus' tree.


We seem to have broken an unusually large amount of stuff this time.

partial post-mortem:

- The ACPICA merge landed in -mm super-late: basically it was in mainline
  a week afterwards and saw only a single -mm release.

  Part of the reason for this short period in -mm was that ACPICA had its
  paws all over x86_64 code and conflicted badly with significant changes
  in the x86_64 tree.

  That happens sometimes.  But when it does, the mess lands in my lap
  rather than in the laps of the perpetrators.

  Lesson: keep the code well-factored so that different subsystems don't
  soil each others' kennels.

- The hrtimers/dynticks stuff is simply hard: timekeeping, low-level x86,
  even APICs.  These are areas in which things break a lot, so churning it
  was inevitably going to cause problems.

  Lesson: none, I think.  Low-level x86 support is just hard, and
  changing it breaks things.


So that accounts for _some_ of the damage, but I wonder if there's more to
it than that.

Re: [1/6] 2.6.21-rc2: known regressions

[Greg KH]

On Mon, Mar 05, 2007 at 02:50:31AM +0100, Adrian Bunk wrote:
> Subject    : kref refcounting breakage
> References : http://lkml.org/lkml/2007/3/2/67
> Submitter  : Andrew Morton <akpm@linux-foundation.org>
> Handled-By : Greg KH <greg@kroah.com>
> Status     : unknown

I'm working on tracking this down still...

> Subject    : wireless breakage (ipw2200, iwconfig, NetworkManager)
> References : http://lkml.org/lkml/2007/3/4/135
> Submitter  : Matt Mackall <mpm@selenic.com>
> Caused-By  : Greg Kroah-Hartman <gregkh@suse.de> (?)
>              commit 43cb76d91ee85f579a69d42bc8efc08bac560278 (?)
> Handled-By : Johannes Berg <johannes@sipsolutions.net>
> Status     : unknown

I really think this is a CONFIG_SYSFS_DEPRECATED issue (not being set),
but want to get Matt confirm either way before saying this is a real
issue or not.

thanks,

greg k-h

Re: [1/6] 2.6.21-rc2: known regressions

[Johannes Berg]

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On Sun, 2007-03-04 at 19:35 -0800, Greg KH wrote:

> > Subject    : wireless breakage (ipw2200, iwconfig, NetworkManager)
> > References : http://lkml.org/lkml/2007/3/4/135
> > Submitter  : Matt Mackall <mpm@selenic.com>
> > Caused-By  : Greg Kroah-Hartman <gregkh@suse.de> (?)
> >              commit 43cb76d91ee85f579a69d42bc8efc08bac560278 (?)
> > Handled-By : Johannes Berg <johannes@sipsolutions.net>
> > Status     : unknown
> 
> I really think this is a CONFIG_SYSFS_DEPRECATED issue (not being set),
> but want to get Matt confirm either way before saying this is a real
> issue or not.

I just tested on my quad powermac that also runs a stock Debian/unstable
and changing that option makes all the difference. Nevermind that it
defaults to yes and one needs to turn it off explicitly...

johannes

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Re: [1/6] 2.6.21-rc2: known regressions

[Greg KH]

On Sun, Mar 04, 2007 at 11:01:33PM -0500, Mark Lord wrote:
> Adrian Bunk wrote:
> >
> >Subject    : Bluetooth RFComm locks up the machine  (device_move() related)
> >References : http://lkml.org/lkml/2007/3/4/64
> >Submitter  : Mark Lord <lkml@rtr.ca>
> >Caused-By  : Marcel Holtmann <marcel@holtmann.org>
> >             commit c1a3313698895d8ad4760f98642007bf236af2e8
> >Status     : unknown
> 
> A 2-line patch exists for fs/sysfs/dir.c to address this.
> Waiting on Greg to apply it or substitute something prettier.  ;)

I want to see if Marcel agrees with it, as he did the original patch in
that area.

thanks,

greg k-h

Re: [1/6] 2.6.21-rc2: known regressions

[Marcel Holtmann]

Hi Greg,

> > >Subject    : Bluetooth RFComm locks up the machine  (device_move() related)
> > >References : http://lkml.org/lkml/2007/3/4/64
> > >Submitter  : Mark Lord <lkml@rtr.ca>
> > >Caused-By  : Marcel Holtmann <marcel@holtmann.org>
> > >             commit c1a3313698895d8ad4760f98642007bf236af2e8
> > >Status     : unknown
> > 
> > A 2-line patch exists for fs/sysfs/dir.c to address this.
> > Waiting on Greg to apply it or substitute something prettier.  ;)
> 
> I want to see if Marcel agrees with it, as he did the original patch in
> that area.

I am not deep enough in the sysfs code to tell you if Mark's change it
correct or not. It looks however fully reasonable to me. From the higher
level perspective of the device_move() usage the RFCOMM code looks
correct and has been tested before I submitted it for inclusion.

Regards

Marcel