On Friday, 23 August 2002 at 15:58:17 -0500, Doug Swarin wrote:
> On Fri, Aug 23, 2002 at 09:20:02PM +0100, Peter Edwards wrote:
>> "Peter Edwards" <[EMAIL PROTECTED]> wrote:
>> Urgh. Forget it, I was seeing references to rq that weren't there.
>>
>>> Hi,
>>>
>>> Ok, I'm up to my neck in code I've never seen and making wild
>>> guesses, but:
>>>
>>> In vinumrequest.c:launch_requests(), isn't it possible that the
>>> final BUF_STRATEGY() from line 431 completes before we get back to
>>> the top of the outer "for" loop and that complete_rqe gets called
>>> for the last buffer (we don't have splbio()), bringing the
>>> refcount of the entire request down to zero, then freeing the
>>> request. You then get to the top of the loop, and rq will have
>>> been freed, but you looking at its contents. Ok, maybe not likely
>>> but...
>>>
>>> I suppose you could just hold one more reference to the request
>>> while doing launch_requests() and check after all theB UF_STRATEGYs
>>> are done when you decrement the active count and find it's zero,
>>> then do the "request-finished" processing as done by complete_rqe
>>> Just a thought...
>
> I've already got a patch for this; it's in PR kern/41740, along with
> another that allows you to safely hot-revive a striped plex.

I checked in the first patch a couple of hours ago.  It seems that it
only affected ATA drives, which is why I wasn't able to reproduce it.

The second patch is less obvious.  It doesn't take into account that
RAID plexes are also striped.  I'll discuss this with you in private
mail.

Greg
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