[DRBD-user] Oops when shutting down drbd

Lars Ellenberg lars.ellenberg at linbit.com
Wed Aug 1 15:29:20 CEST 2007


On Wed, Aug 01, 2007 at 10:16:35AM +0200, Rainer Sabelka wrote:
> Hi Lars,
> 
> thanks for your answer!
> 
> On Tuesday 31 July 2007 22:10, Lars Ellenberg wrote:
> > On Tue, Jul 31, 2007 at 05:58:09PM +0200, Rainer Sabelka wrote:
> [...]
> > > Jul 30 14:57:40 newserver2 kernel: drbd0: drbd_bm_resize:
> > > (down_trylock(&b->bm_change)) in
> > > /usr/src/modules/drbd/drbd/drbd_bitmap.c:370 Jul 30 14:57:40 newserver2
> > > kernel: drbd0: drbd_bm_resize called with capacity == 1409178656
> >
> > so you do have ~ 1.4 TB of storage.
> 
> No. The partition I use for DRBD has 704610868 kB, so this apoprox. the half.

right. we report sectors there...

> > > [...]
> > it may be that you see two problems:
> > first, some race condition accessing the bitmap,
> > second the debug aid that should help in finding the cause of the race
> > condition dereferencing a NULL pointer in a debug printk...
> >
> > and that NULL pointer would be the mdev->bitmap,
> > compare with drbd_bitmap.c ~ line 780 (drbd_bm_rw)...
> > and the printk in the __drbd_bm_lock function...
> 
> Hmmm...  with printk you mean the line
> 
> 	ERR("%s:%d: bitmap already locked by %s:%lu\n",
>  		file, line, b->bm_file,b->bm_line);
> 
> 
> in __drbd_bm_lock()?
> 
> If b (=mdev->bitmap) is NULL here, then the crash would be before calling 
> printk(), wouldn't it?

right.

> Could it be that b->bm_file is NULL?

no.

so this suspicion has just been proved wrong :)

-- 
: Lars Ellenberg                            Tel +43-1-8178292-0  :
: LINBIT Information Technologies GmbH      Fax +43-1-8178292-82 :
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