Centos-6 kernel soft lockup CPU#20 stuck for 67s! [smbd-notifyd] after upgrade form 4.2 to 4.4

[Alexander Bokovoy]

On Mon, 02 May 2016, Stefan Metzmacher wrote:
> Am 02.05.2016 um 16:05 schrieb Alexander Bokovoy:
> > On Mon, 02 May 2016, Dr. Hansjoerg Maurer wrote:
> >> Hi
> >>
> >> thank you for your fast reply.
> >>
> >> Do you have any further information (e.g. is there already  a bug
> >> report at Redhat ? which kernel is affected? which subsystem causes
> >> that problem? ...)
> >>
> >> I can open a bug at RedHat, but I would need more information.
> >>
> >> Sould I open a samba bugzilla entry  in order to  get  it documented
> >> for other people who run into the sambe problem with samba > 4.2 and
> >> RHEL-6/Centos-6 (not an exotic plattform :-) )
> > Well, what you could do if you have RHEL subscription, is to make a bug
> > at Red Hat for kernel and try to get that fixed. Note that Samba > 4.2
> > most likely will not be backported to RHEL 6.x in a supported (by Red
> > Hat) way but if you could find out a way to reproduce it without Samba,
> > the bug would have good weight to fix -- perhaps it is already fixed
> > kernel upstream and the question is more of backporting that.
> > 
> >>>> I checked the release notes for 4.3.0  and found, that there have
> >>>> been changes in the  FileChangeNotify subsystem
> >>>
> >>> Yes, we are using unix domain datagram sockets more excessively now.
> >>> The kernel does not like it, although it is a pretty standard API.
> >>>
> >>>> Does anybody else has problems in this area.
> >>>>
> >>>> We will try it again with
> >>>>
> >>>>  kernel change notify = no
> >>>
> >>> Won't help. Downgrade Samba to 4.2 and wait for the next CentOS kernel
> >>> to fix the issue.
> > Volker, do you know if this is actually a known bug kernel upstream?
> 
> Yes, see https://bugs.launchpad.net/bugs/1543980
Ah, that one. Thanks.


-- 
/ Alexander Bokovoy