netdev - Re: [PATCH net] sctp: sctp should release assoc when sctp_make_abort_user return NULL in sctp

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Message-ID: <20151218162357.GB5050@mrl.redhat.com>
Date:	Fri, 18 Dec 2015 14:23:57 -0200
From:	Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
To:	Vlad Yasevich <vyasevich@...il.com>
Cc:	Xin Long <lucien.xin@...il.com>,
	network dev <netdev@...r.kernel.org>,
	linux-sctp@...r.kernel.org, vyasevic@...hat.com,
	davem@...emloft.net
Subject: Re: [PATCH net] sctp: sctp should release assoc when
 sctp_make_abort_user return NULL in sctp_close

On Fri, Dec 18, 2015 at 09:08:46AM -0500, Vlad Yasevich wrote:
> On 12/17/2015 02:33 PM, Vlad Yasevich wrote:
> > On 12/17/2015 02:01 PM, Marcelo Ricardo Leitner wrote:
...
> >> There is a check on sctp_cmd_delete_tcb() that avoids calling that on temp assocs on
> >> listening sockets, but that condition is false due to the check on sk_shutdown so it will
> >> call those two functions anyway.
> > 
> > The condition I am a bit concerned about is one thread waiting in sctp_wait_for_sndbuf
> > while another does an abort.
> > 
> > I think this is OK though.  I need to look a bit more...
> 
> I think the only time this ends up biting us is if SO_SNDTIMEO was used and we ran out
> of send buffer.  It looks to me like schedule_timeout() will wait until timer expired and
> depending on the timer value, you could wait quite a while.
> 
> With this path, since you don't transition state, the asoc->wait wait queue is never
> notified and it could be hanging around for quite a while.

Yes, agreed. For blocking sockets, it could hang waiting until the
application finally closes. Thanks Vlad.

  Marcelo

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