linux-kernel - Re: PROBLEM: Silent data corruption when using sendfile()

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20120714083136.GO16256@1wt.eu>
Date:	Sat, 14 Jul 2012 10:31:36 +0200
From:	Willy Tarreau <w@....eu>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Hillf Danton <dhillf@...il.com>,
	Johannes Truschnigg <johannes@...schnigg.info>,
	linux-kernel@...r.kernel.org, Linux-Netdev <netdev@...r.kernel.org>
Subject: Re: PROBLEM: Silent data corruption when using sendfile()

On Sat, Jul 14, 2012 at 10:20:41AM +0200, Eric Dumazet wrote:
> > On Tue, Jul 3, 2012 at 8:02 AM, Willy Tarreau <w@....eu> wrote:
> > >
> > > In fact it has been true zero copy in 2.6.25 until we faced a large
> > > amount of data corruption and the zero copy was disabled in 2.6.25.X.
> > > Since then it remained that way until you brought your patches to
> > > re-instantiate it.
> 
> Might be, or not (could be a NIC bug)

I may be wrong but what I recall from this bug was an issue when
forwarding TCP between two NICs, related to linear vs non-linear
data (I have memories of something around data not yet ACKed being
replaced before being retransmitted but I may be wrong). Anyway,
the way it was fixed consisted in simply disabling the zero-copy
code path. So this should be something different from what Johannes
reports. Maybe a regression since then though.

> Please Johannes could you try latest kernel tree ?

It would be useful, especially given the amount of changes you performed
in this area in latest version, it could be very possible that this new
bug got fixed as a side effect !

Regards,
Willy

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/