Hi folks,
There seems to be a potential deadlock in the sd_open path. The problem
is this while loop:
...
while (rscsi_disks[target].device->busy) {
barrier();
cpu_relax();
}
...
In revalidate_scsidisk we do this:
...
device->busy = 1;
...
almost certain schedule();
...
device-busy = 0;
Both paths hold the kernel lock so if sd_open gets into the while loop when
the revalidate is sleeping it's all over.
As a simple preventative fix I'd say put a schedule in the while loop. It's
a little ugly, but less intrusive that adding a wait queue to the device.
Anoyone see anything wrong with doing that? Other solutions?
This seems to be present in 2.0, 2.2. and 2.4 (where we hit it).
The while-forever-loop-with -kernel-lock seems to be gone in 2.5.
Cheers,
Phil
-- Philip R. Auld, Ph.D. Technical Staff Egenera Corp. pauld@egenera.com 165 Forest St., Marlboro, MA 01752 (508)858-2600 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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