From: "Timo Teräs" <timo.teras@iki•fi>
To: Mark Brown <broonie@opensource•wolfsonmicro.com>
Cc: "David S. Miller" <davem@davemloft•net>, netdev@vger•kernel.org
Subject: Re: [PATCH] xfrm: Fix double dst_release() in xfrm_lookup() -EREMOTE case
Date: Thu, 08 Apr 2010 15:39:38 +0300 [thread overview]
Message-ID: <4BBDCE8A.7040106@iki.fi> (raw)
In-Reply-To: <1270729773-1758-1-git-send-email-broonie@opensource.wolfsonmicro.com>
Mark Brown wrote:
> Commit 80c802 ("xfrm: cache bundles instead of policies for outgoing
> flows") changed __xfrm_policy() to call dst_release() when returning
> -EREMOTE. In the case where this is called from xfrm_lookup() a double
> call to dst_release() would result due to the existing dst_release()
> there. Remove the dst_release() in xfrm_lookup().
>
> Signed-off-by: Mark Brown <broonie@opensource•wolfsonmicro.com>
> ---
>
> I'm not sure if this is correct or not - there may a reference been
> taken earlier in __xfrm_lookup() that's being dropped but I didn't spot
> it.
This is not correct.
The only case we return -EREMOTE from __xfrm_policy() is at:
if (net->xfrm.sysctl_larval_drop) {
/* EREMOTE tells the caller to generate
* a one-shot blackhole route. */
dst_release(dst);
xfrm_pols_put(pols, num_pols);
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTNOSTATES);
return -EREMOTE;
}
It drops the inner xfrm_dst returned from flow cache lookup / resolver.
xfrm_lookup() will drop the original dst (which is not xfrm_dst).
This semantics is important because __xfrm_lookup() is also called
from other places, that do other things when they get -EREMOTE.
- TImo
next prev parent reply other threads:[~2010-04-08 12:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-08 12:29 [PATCH] xfrm: Fix double dst_release() in xfrm_lookup() -EREMOTE case Mark Brown
2010-04-08 12:39 ` Timo Teräs [this message]
2010-04-08 13:43 ` Mark Brown
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