From mboxrd@z Thu Jan  1 00:00:00 1970
From: Vlad Yasevich <vyasevich@gmail.com>
Date: Wed, 05 Dec 2012 17:11:02 +0000
Subject: Re: Possible SCTP peer receive window bug
Message-Id: <50BF8026.9040500@gmail.com>
List-Id: <linux-sctp.vger.kernel.org>
References: <B1BF0D5B21C20F4D8AE9BB4366C9BFCA6D387197@ENFIRHMBX1.datcon.co.uk>
In-Reply-To: <B1BF0D5B21C20F4D8AE9BB4366C9BFCA6D387197@ENFIRHMBX1.datcon.co.uk>
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To: linux-sctp@vger.kernel.org

On 12/05/2012 11:30 AM, Neil Horman wrote:
> On Tue, Dec 04, 2012 at 09:58:35AM -0500, Neil Horman wrote:
>> On Tue, Dec 04, 2012 at 01:34:54PM +0000, Jamie Parsons wrote:
>>> Hi Neil and Vlad,
>>>
>>> I've spoken to IT services and they can install the Fedora 17 OS on a box for me.  Is that recent enough a kernel to repro the issue on?
>>>
>>> Thanks,
>>>
>>> Jamie
>>>
>> Yes, it is I think.  Vlad and I have also discussed this and we think a
>> systemtap script might be in order here so we can better track what the rwnd
>> value is doing as your test case progresses.  I'm sorry I've not gotten that to
>> you yet, but I'm working on it.
>> Neil
>>
>
>
> So, I have to apologize, but systemtap kinda sucks to work with.  Its not
> working yet, but I wanted to post this too you in case you have better systemtap
> skills than I do.  Regardless this stap script is generall the thing we want to
> run and should give us a fairly good view (when it works) of whats happening
> with an associations peer rwnd value in the stack.
>
> Best
> Neil
>
>
> probe module("sctp").function("sctp_assoc_update").return {
> 	printf("sctp_assoc_update updates asoc %p peer rwnd to %d\n", $asoc, $asoc->peer->rwnd);
> }
>
>
> probe module("sctp").function("sctp_retransmit_mark") {
> 	printf("sctp_retransmit_mark increases asoc %p peer rwnd to %d\n", $asoc, $q->asoc->peer->rwnd);
> }
>

shouldn't the above be ".return"?  Otherwise, we are triggered at 
function start.  might be worth a try to probe both start and end
and see what the diff.

> probe module("sctp").function("sctp_outq_sack") {
> 	printf("sctp_outq_sack updates asoc %p peer rwnd to %d\n", $q->asoc, $q->asoc->peer->rwnd);
> }
>

Same here...

-vlad

> probe module("sctp").function("sctp_packet_append_data").return {
> 	printf("sctp_packet_append_data reduces asoc %p peer rwnd to %d\n", $asoc, $asoc->peer->rwnd);
> }
>
> probe module("sctp").function("sctp_process_init").return {
> 	printf("sctp_process_init updates assoc %p peer rwnd to %d\n", $asoc, $asoc->peer->rwnd);
> }
>
>