Re: list corruption in the last few days. (block ? crypto ?)

[Dave Jones <davej@redhat.com>]

On Fri, Aug 05, 2011 at 11:32:09AM -0500, Christoph Lameter wrote:
 > On Fri, 5 Aug 2011, Pekka Enberg wrote:
 > 
 > > On Fri, Aug 5, 2011 at 11:46 AM, Markus Trippelsdorf
 > > <markus@trippelsdorf.de> wrote:
 > > > On 2011.08.04 at 21:00 -0400, Dave Jones wrote:
 > > >> Sometime in the last week, something was merged which causes my laptop
 > > >> to lock up occasionally.  I can trigger it most of the time just by
 > > >> doing a kernel build. When it gets to the final linking stage, it locks up hard.
 > > >>
 > > >> I finally managed to coax something out of usb console to get the traces below,
 > > >> which seem to implicate something in the block layer ?
 > > >>
 > > >> my root device is an lvm volume on an dmcrypt'd block dev, which might be relevant,
 > > >> as I don't see this happening on other machines with simpler setups.
 > > >>
 > > >> I'm going to try bisecting, but it might take me a few days, because it's
 > > >> such a pain in the ass to reproduce this reliably.
 > > >>
 > > >> [ 5913.233035] ------------[ cut here ]------------
 > > >> [ 5913.233097] WARNING: at lib/list_debug.c:53 __list_del_entry+0x8d/0x98()
 > > >> [ 5913.233101] Hardware name: Adamo 13
 > > >> [ 5913.233105] list_del corruption. prev->next should be ffffea000434fd20, but was ffffea0004199520
 > > >
 > > > See also: http://lkml.org/lkml/2011/8/3/37
 > >
 > > That's in networking so SLUB lockless patches are almost certainly the
 > > issue here. Is this with SLUB debugging enabled or not? Christoph, it
 > > like the partial lists are getting corrupted somehow.
 > 
 > This is occurring in __slab_free when we are freeing the last
 > object from a slab page that is on the partial list. It is not frozen so
 > it is not in use by a processor and thus deactivate_slab cannot be run
 > on it.
 > 
 > The logical race would be with acquire_slab() but both take the node lock
 > before doing anything with the lists.
 > 
 > Do you have CONFIG_DEBUG_VM on? If not please do so. This will check if
 > the frozen state is managed correctly.

Not sure if you were addressing my original report (quoted above), or the networking
related report in this part of the thread. But anyway, I had it turned on (as well as just about
every other debugging option).  I didn't see anything output from it though,
just the LIST_DEBUG warnings.

	Dave