Re: [linux-pm] OOPS: divide error while s2dsk (2.6.20-rc1-mm1)

[Nigel Cunningham <nigel@nigel.suspend2.net>]

Hi.

On Mon, 2006-12-18 at 23:38 +0100, Rafael J. Wysocki wrote:
> On Monday, 18 December 2006 18:02, Jiri Slaby wrote:
> > Rafael J. Wysocki wrote:
> > > Hi,
> > > 
> > > On Monday, 18 December 2006 12:20, Jiri Slaby wrote:
> > >> Hi.
> > >>
> > >> I got this oops while suspending:
> > >> [  309.366557] Disabling non-boot CPUs ...
> > >> [  309.386563] CPU 1 is now offline
> > >> [  309.387625] CPU1 is down
> > >> [  309.387704] Stopping tasks ... done.
> > >> [  310.030991] Shrinking memory... -<0>divide error: 0000 [#1]
> > >> [  310.456669] SMP
> > >> [  310.456814] last sysfs file:
> > >> /devices/pci0000:00/0000:00:1e.0/0000:02:08.0/eth0/statistics/collisions
> > >> [  310.456919] Modules linked in: eth1394 floppy ohci1394 ide_cd ieee1394 cdrom
> > >> [  310.457259] CPU:    0
> > >> [  310.457260] EIP:    0060:[<c0150c9a>]    Not tainted VLI
> > >> [  310.457261] EFLAGS: 00210246   (2.6.20-rc1-mm1 #207)
> > >> [  310.457478] EIP is at shrink_slab+0x9e/0x169
> > > 
> > > Looks like we have a problem with slab shrinking here.
> > > 
> > > Could you please use gdb to check what exactly is at shrink_slab+0x9e?
> > 
> > Sure, but not till Friday, sorry (I am away).
> 
> I reproduced this on one box, but then it turned out that EIP was at line 195
> of mm/vmscan.c where there was
> 
> do_div(delta, lru_pages + 1);
> 
> Well, I have no idea how this can lead to a divide error (lru_pages is
> unsigned).
> 
> I'm unable to reproduce this on another i386 box, so it seems to be somewhat
> configuration specific.
> 
> Does 2.6.20-rc1 work for you?

I have a patch in -mm that reduces lru_pages by what shrink_all_zones
returns. Could shrink_all_zones perhaps be returning incorrect values
such that lru_pages ends up becoming -1?

Regards,

Nigel