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

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Message-Id: <20200610.160604.1148281043237238325.davem@davemloft.net>
Date:   Wed, 10 Jun 2020 16:06:04 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     pabeni@...hat.com
Cc:     netdev@...r.kernel.org, kuba@...nel.org, mptcp@...ts.01.org
Subject: Re: [PATCH net] mptcp: fix races between shutdown and recvmsg

From: Paolo Abeni <pabeni@...hat.com>
Date: Wed, 10 Jun 2020 10:47:41 +0200

> 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>

Applied, thanks Paolo.