Re: Fw: crash on x86_64 - mm related?

From: Kai Makisara
Date: Tue Nov 29 2005 - 15:47:33 EST


On Tue, 29 Nov 2005, Ryan Richter wrote:

> On Tue, Nov 29, 2005 at 10:04:39PM +0200, Kai Makisara wrote:
> > I looked at the driver and it seems that there is a bug: st_write calls
> > release_buffering at the end even when it has started an asynchronous
> > write. This means that it releases the mapping while it is being used!
> > (I wonder why this has not been noticed earlier.)
> >
> > The patch below (against 2.6.15-rc2) should fix this bug and some others
> > related to buffering. It is based on the patch "[PATCH] SCSI tape direct
> > i/o fixes" I sent to linux-scsi on Nov 21. The patch restores setting
> > pages dirty after reading and clears number of s/g segments when the
> > pointers are not valid any more.
> >
> > The patch has been lightly tested with AMD64.
>
> This applies cleanly to 2.6.14.2, do you forsee any problems using it
> with that kernel? I'd like to not change too many things at once.
>
No, I don't see any potential problems applying this patch to 2.6.14.2.
There is nothing specific to 2.6.15-rc2.

If someone sees that there is something wrong, please yell. The
main purpose of the patch is not to call release_buffering() at the end of
st_write() when starting asynchronous write and call it in
write_behind_check() instead.

> If it should be OK, I'll boot this tonight or tomorrow - the backups run
> every other night, so it won't get any testing until tomorrow night.
>
> Thanks a lot,
> -ryan
>
Thanks for reporting the problem and thanks in advance for testing.

--
Kai
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