Re: [PATCH] net: fix race in the receive/select
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: 2009-07-01 13:08:19
Also in:
lkml
Possibly related (same subject, not in this thread)
- 2009-06-29 · Re: [PATCH] net: fix race in the receive/select · Jiri Olsa <hidden>
- 2009-06-29 · Re: [PATCH] net: fix race in the receive/select · Jiri Olsa <hidden>
- 2009-06-28 · Re: [PATCH] net: fix race in the receive/select · Jarek Poplawski <hidden>
- 2009-06-28 · Re: [PATCH] net: fix race in the receive/select · Oleg Nesterov <oleg@redhat.com>
- 2009-06-28 · Re: [PATCH] net: fix race in the receive/select · Jarek Poplawski <hidden>
On Wed, Jul 01, 2009 at 06:58:52PM +0800, Herbert Xu wrote:
It would be good to know whether this bug occurs on the upstream kernel because as it stands, the patch is a no-op for the upstream kernel on x86-64.
I take that back. Andi, please look at section 8.2.3.4 of the IA-32 Architectures Software Developer's Manual Volume 3A, "Loads May Be Reordered with Earlier Stores to Different Locations. This seems to be exactly the scenario that we have here, and shows why mfence is required. In our case, we're doing CPU1 CPU2 Write data ready Add ourselves to wait queue Read wait queue to notify Check data ready Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} [off-list ref] Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt