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

[Gene Heskett <gene.heskett@gmail.com>]

On Monday 19 March 2007, 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.
>
>James

James, could this also be the cause of a tar based backup going crazy and 
thinking all data is new under any 2.6.21-rc* kernel I've tested so far 
with amanda, which in my case uses tar?  I've tried the fedora patched 
tar-1.15-1, and one I hand built right after 1.15-1 came out over a year 
ago, and they both do it, but only when booted to a 2.6.21-rc* kernel.

This obviously will be a show-stopper, either for amanda (and by 
inference, any app that uses tar), or for the migration of an amanda 
users machinery to a 2.6.21 kernel.

>
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-- 
Cheers, Gene
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