Re: 2.6.20.3: kernel BUG at mm/slab.c:597 try#2

[Mike Christie <michaelc@cs.wisc.edu>]

Mike Christie wrote:
> James Bottomley wrote:
>> On Mon, 2007-03-19 at 12:49 -0500, Mike Christie wrote:
>>>> I can't even say if the tapes are written correctly as I can't read them
>>>> (one does not reboot production machines back to 2.4.x just to try to
>>>> read a backup tape - I don't have 2.6.x older than 2.6.20 on these
>>>> machines).
>>> Could you try this patch
>>> http://marc.info/?l=linux-scsi&m=116464965414878&w=2
>>> I thought st was modified to not send offsets in the last elements but
>>> it looks like it wasn't.
>> Actually, there are two patches in the email referred to.  If the
>> analysis that we're passing NULL to mempool_free is correct, it should
>> be the second one that fixes the problem (the one that checks
>> bio->bi_io_vec before freeing it).  Which would mean we have a
>> nr_vecs==0 bio generated by the tar somehow.
>>
> 
> I think we might only need the first patch if the problem is similar to
> what the lsi guys were seeing. I thought the problem is that we are not
> estimating how large the transfer is correctly because we do not take
> into account offsets at the end. This results in nr_vecs being zero when
> it should be a valid value. I thought Kai's patch:
> http://bugzilla.kernel.org/show_bug.cgi?id=7919
> http://git.kernel.org/?p=linux/kernel/git/jejb/scsi-misc-2.6.git;a=commitdiff;h=9abe16c670bd3d4ab5519257514f9f291383d104
> fixed the problem on st's side,

Oh, I noticed that the subject for the mail references 2.6.30.3 and the
patch for st in the bugzilla did not make into 2.6.20 and is not in .3.
Could we try the st patch in the bugzilla first?