netdev - Re: [MPTCP] [PATCH net] mptcp: fix races between shutdown and recvmsg

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Message-ID: <f9ae8422-583f-24d3-c5f4-776f24e788dc@tessares.net>
Date:   Wed, 10 Jun 2020 12:04:00 +0200
From:   Matthieu Baerts <matthieu.baerts@...sares.net>
To:     Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org
Cc:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, mptcp@...ts.01.org
Subject: Re: [MPTCP] [PATCH net] mptcp: fix races between shutdown and recvmsg

Hi Paolo,

On 10/06/2020 10:47, Paolo Abeni wrote:
> The msk sk_shutdown flag is set by a workqueue, possibly
> introducing some delay in user-space notification. If the last
> subflow carries some data with the fin packet, the user space
> can wake-up before RCV_SHUTDOWN is set. If it executes unblocking
> recvmsg(), it may return with an error instead of eof.
> 
> Address the issue explicitly checking for eof in recvmsg(), when
> no data is found.
> 
> Fixes: 59832e246515 ("mptcp: subflow: check parent mptcp socket on subflow state change")
> Signed-off-by: Paolo Abeni <pabeni@...hat.com>

Thank you for the patch, it looks good to me!

Reviewed-by: Matthieu Baerts <matthieu.baerts@...sares.net>

Cheers,
Matt
-- 
Matthieu Baerts | R&D Engineer
matthieu.baerts@...sares.net
Tessares SA | Hybrid Access Solutions
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