[Crash-utility] crash problems with linux-4.5

[Steve Wise]

> > > > > Hi,
> > > > >
> > > > > Just forcing a crash dump via 'echo c > /proc/sysrq-trigger' results
> > > > > in a crash
> > > > > dump that has no tasks saved.  I see _lots_ of these errors when
> > > > > loading the
> > > > > dump with the latest crash from the git repo:
> > > > >
> > > > > crash: page excluded: kernel virtual address: ffff88103c5a9000
> > > > > type:
> > "fill_task_struct"
> > > > > WARNING: active task ffff881078a04340 on cpu 3 not found in PID hash
> > > > >
> > > > > Then nothing is in the dump:
> > > > >
> > > > > crash> ps
> > > > >    PID    PPID  CPU       TASK        ST  %MEM     VSZ    RSS  COMM
> > > > > >     0      0   0  ffffffff81c0f4c0  RU   0.0       0      0
> > > > > > [swapper/0]
> > > > > crash>
> > > > >
> > > > > Any ideas?
> > > > >
> > > > > I'm using top-o-tree from Dave's git repo
> > > > > https://github.com/crash-utility/crash.git:
> > > > >
> > > > > commit 04ab5c560a58246e782509d99214afcaf8462b4c
> > > > > Author: Dave Anderson <anderson at redhat.com>
> > > > > Date:   Tue Mar 1 16:16:48 2016 -0500
> > > > >
> > > > >     Put 2016 copyright in initial banner.
> > > > >
> > > > >
> > > > > Thanks,
> > > > >
> > > > > Steve.
> > > >
> > > > If you have configured kdump to use makedumpfile -d31, it is probably
> > > > this:
> > > >
> > > >   [Crash-utility] makedumpfile: 4.5 kernel commit breaks page
> > > > filtering
> > > >
> > > > https://www.redhat.com/archives/crash-utility/2016-February/msg00009.html
> > > >
> > > > > PS: I'm not on the crash-utility list, so please include my email in
> > > > > any
> > > > > replies.
> > > >
> > > > PS: if you're using crash on bleeding edge kernels, you might want to
> > > > join
> > > > the list, at least in digest mode.
> > >
> > > Thanks Dave. I've joined. :)
> > >
> > > I changed the makedumpfile line in /etc/init.d/kdump from -d 31 to -d
> > > 17,
> > > then removed the kdump initrd from /boot, and restarted kdump to
> > > generate
> > > the new initrd file.  I then rebooted, and produced a new crash dump.
> > > But
> > > I'm still seeing the same issue.
> > >
> > > Am I doing the correct procedure for forcing makedumpfile to use -d17?
> >
> > I think so, yes.  And downgrading to -d17 seems to have worked, at least
> > for
> > the two reporter on this list.  You can verify that the -d configuration
> > is as
> > expected by entering:
> >
> >  crash> help -D | grep dump_level
> >
> 
> Hmm: still using 31:
> 
> crash> help -D|grep dump_level
>           dump_level: 31 (0x1f)
> (DUMP_EXCLUDE_ZERO|DUMP_EXCLUDE_CACHE|DUMP_EXCLUDE_CACHE_PRI|D
> UMP_EXCLUDE_USER_DATA|DUMP_EXCLUDE_FREE)
> crash>
> 
> Apparently the makedumpfile parameters being used are not the ones in
> /etc/init.d/kdump.
> 

Found it: The makedumpefile settings used are in /etc/kdump.conf.  :)

Steve.