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

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Date:	Mon, 21 Dec 2015 17:56:15 +0800
From:	Xin Long <lucien.xin@...il.com>
To:	Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
Cc:	Vlad Yasevich <vyasevich@...il.com>,
	network dev <netdev@...r.kernel.org>,
	linux-sctp@...r.kernel.org, Vlad Yasevich <vyasevic@...hat.com>,
	davem <davem@...emloft.net>
Subject: Re: [PATCH net] sctp: sctp should release assoc when
 sctp_make_abort_user return NULL in sctp_close

On Sat, Dec 19, 2015 at 12:23 AM, Marcelo Ricardo Leitner
<marcelo.leitner@...il.com> wrote:
> 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.

do you think it makes sense if we have this condition judgment there ?
        if (waitqueue_active(&asoc->wait))
            wake_up_interruptible(&asoc->wait);


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