Re: kernel BUG at drivers/scsi/aic7xxx/aic79xx_osm.c:1490!

FUJITA Tomonori
2008-03-09T12:29:34Z

On Sun, 09 Mar 2008 14:23:13 +0300
Michael Tokarev <mjt@tls.msk.ru> wrote:

> Just got quite.. bad situation on a production server
> here. The machine locked up hard several times in a
> row (required hard reboot). So I finally enabled watchdog
> subsystem which helped.
>
> Now I see the following (over netconsole):
>
> DMA: Out of SW-IOMMU space for 65536 bytes at device 0000:08:07.0
> ------------[ cut here ]------------
> kernel BUG at drivers/scsi/aic7xxx/aic79xx_osm.c:1490!

Seems that you was out of swiommu space (and aic79xx can't handle it
though it should). This happened because:

a) you produced more I/Os than swiommu can handle.

b) swiommu space leaks due to bugs.

If you hit this problem due to a), the following boot option might
help:

swiotlb=65536

The same machine run well with old kernels? If so, probably, 2.6.24
has new bugs that lead to swiommu space leak.