Re: highmem deadlock fix [was Re: VM in 2.4.10(+tweaks) vs. 2.4.9-ac14/15(+stuff)]

Robert Macaulay
2001-09-28T02:12:37Z

On Thu, 27 Sep 2001, Andrea Arcangeli wrote:

>
> Moving clear_bit just above submit_bh will fix it (please Robert make
> this change before testing it), because if we block in submit_bh in the
> bounce, then we won't deadlock on ourself because of the pagehighmem
> check, and all previous non-pending bh are ok too, (only the next are
> problematic, and they're still marked pending_IO so we can't deadlock on
> them).
>
It worked. The box did not freeze.

We can try Linus' patch as well if needed. I had actually applied
it and rebooted before the warning, and as predicted, it froze very
early in the boot process.

Thanks Andrea. I'll see if we can repeat the 0-page alloc again.
Robert