Re: [OOPS] 2.6.21-rc6-git5 in cfq_dispatch_insert

[Brad Campbell <brad@wasp.net.au>]

Jens Axboe wrote:

> It looks to be extremely rare. Aliases are extremely rare, front merges
> are rare. And you need both to happen with the details you outlined. But
> it's a large user base, and we've had 3-4 reports on this in the past
> months. So it obviously does happen. I could not make it trigger without
> doctoring the unplug code when I used aio.

Well, not that rare on this particular machine (I had a case where I could reproduce it in less than 
an hour of normal use previously on this box), and I've had it occur a number of times on my 
servers, I just never reported it before as I never took the time to set up a serial console and 
capture the oops.

> Here's a fix for it, confirmed.

Shall I leave the other debugging in, apply this and run it for a few hard days?

Brad
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