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SubjectRe: [PATCH] 2.6.0 NBD driver: remove send/recieve race for request
Lou Langholtz wrote:
>
> The following patch removes a race condition in the network block device
> driver in 2.6.0*. Without this patch, the reply receiving thread could
> end (and free up the memory for) the request structure before the
> request sending thread is completely done accessing it and would then
> access invalid memory.

Indeed, there is a race condition here. It's a very small window, but it
looks like it could possibly be trouble on SMP/preempt kernels.

This patch looks OK, but it appears to still leave the race window open
in the error case (it seems to fix the non-error case, though). We
probably could actually use the ref_count field of struct request to
better fix this problem. I'll take a look at doing this, and send a
patch out in a while.

Thanks,
Paul
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