From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: netdev@vger.kernel.org, soheil@google.com, willemb@google.com,
ycheng@google.com, ncardwell@google.com
Subject: Re: [PATCH net] tcp: fix return value for partial writes
Date: Thu, 03 Nov 2016 16:12:53 -0400 (EDT) [thread overview]
Message-ID: <20161103.161253.1115708840443382693.davem@davemloft.net> (raw)
In-Reply-To: <1478122910.7065.396.camel@edumazet-glaptop3.roam.corp.google.com>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 02 Nov 2016 14:41:50 -0700
> From: Eric Dumazet <edumazet@google.com>
>
> After my commit, tcp_sendmsg() might restart its loop after
> processing socket backlog.
>
> If sk_err is set, we blindly return an error, even though we
> copied data to user space before.
>
> We should instead return number of bytes that could be copied,
> otherwise user space might resend data and corrupt the stream.
>
> This might happen if another thread is using recvmsg(MSG_ERRQUEUE)
> to process timestamps.
>
> Issue was diagnosed by Soheil and Willem, big kudos to them !
>
> Fixes: d41a69f1d390f ("tcp: make tcp_sendmsg() aware of socket backlog")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Applied and queued up for -stable.
prev parent reply other threads:[~2016-11-03 20:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-02 21:41 [PATCH net] tcp: fix return value for partial writes Eric Dumazet
2016-11-02 21:47 ` Soheil Hassas Yeganeh
2016-11-03 20:12 ` David Miller [this message]
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