From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tim Chen <tim.c.chen@linux.intel.com>
Subject: Re: [PATCH -next v2] unix stream: Fix use-after-free crashes
Date: Thu, 08 Sep 2011 02:24:48 -0700
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Cc: "Yan, Zheng" <zheng.z.yan@intel.com>,
	"Yan, Zheng" <yanzheng@21cn.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
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	Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
To: Eric Dumazet <eric.dumazet@gmail.com>
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On Thu, 2011-09-08 at 15:28 +0200, Eric Dumazet wrote:
> Le mercredi 07 septembre 2011 =C3=A0 23:26 +0200, Eric Dumazet a =C3=A9=
crit :
> > Le mercredi 07 septembre 2011 =C3=A0 05:01 -0700, Tim Chen a =C3=A9=
crit :
>=20
> > > Eric, are you planning to do a fast path patch that doesn't do pi=
d ref
> > > for the case where CONFIG_PID_NS is not set?
> > >=20
> >=20
> > Yes, I'll try to cook a patch.
>=20
> Thinking a bit more on this issue, I really believe we should not sti=
ck
> pid/cred in skbs sent from a write() system call.

I prefer this approach too.

>=20
> That would break following use case :
>=20
> An application uses a write(fd) and expects a receiver using recvmsg(=
)
> to get process credentials (SCM_CREDENTIALS)
>=20
> This is currently working, but not documented (man unix says ancillar=
y
> data are sent with sendmsg())
>=20
> If everybody agrees, I can send a patch for this : This would speedup
> write()/read() af_unix by an order of magnitude.
>=20

Looking forward to the patch.  This should improve the scalability of
af_unix.

Tim