Re: ipc-msg broken again on 3.11-rc7? (was Re: linux-next: Tree for Jun 21 [ BROKEN ipc/ipc-msg ])

[Sedat Dilek <sedat.dilek@gmail.com>]

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On Fri, Aug 30, 2013 at 10:19 AM, Vineet Gupta <vineetg76@gmail.com> wrote:
> Ping ?
>
> It seems 3.11 is pretty close to releasing but we stil have LTP msgctl08 causing a
> hang (atleast on ARC) for both linux-next 20130829 as well as Linus tree.
>
> So far, I haven't seemed to have drawn attention of people involved.
>

Hi Vineet,

I remember fakeroot was an another good test-case for me to test this
IPC breakage.
Attached is my build-script for Linux-next (tested with Debian/Ubuntu).
( Cannot say if you can play with it in your environment. )

Regards,
- Sedat -

> -Vineet
>
> On 08/29/2013 01:22 PM, Sedat Dilek wrote:
>> On Thu, Aug 29, 2013 at 9:21 AM, Vineet Gupta
>> <Vineet.Gupta1@synopsys.com> wrote:
>>> On 08/29/2013 08:34 AM, Sedat Dilek wrote:
>>>> On Wed, Aug 28, 2013 at 1:58 PM, Vineet Gupta
>>>> <Vineet.Gupta1@synopsys.com> wrote:
>>>>> Hi David,
>>>>>
>
> [....]
>
>>>>> LTP msgctl08 hangs on 3.11-rc7 (ARC port) with some of my local changes. I
>>>>> bisected it, sigh... didn't look at this thread earlier :-( and landed into this.
>>>>>
>>>>> ------------->8------------------------------------
>>>>> 3dd1f784ed6603d7ab1043e51e6371235edf2313 is the first bad commit
>>>>> commit 3dd1f784ed6603d7ab1043e51e6371235edf2313
>>>>> Author: Davidlohr Bueso <davidlohr.bueso@hp.com>
>>>>> Date:   Mon Jul 8 16:01:17 2013 -0700
>>>>>
>>>>>     ipc,msg: shorten critical region in msgsnd
>>>>>
>>>>>     do_msgsnd() is another function that does too many things with the ipc
>>>>>     object lock acquired.  Take it only when needed when actually updating
>>>>>     msq.
>>>>> ------------->8------------------------------------
>>>>>
>>>>> If I revert 3dd1f784ed66 and 9ad66ae "ipc: remove unused functions" - the test
>>>>> passes. I can confirm that linux-next also has the issue (didn't try the revert
>>>>> there though).
>>>>>
>>>>> 1. arc 3.11-rc7 config attached (UP + PREEMPT)
>>>>> 2. dmesg prints "msgmni has been set to 479"
>>>>> 3. LTP output (this is slightly dated source, so prints might vary)
>>>>>
>>>>> ------------->8------------------------------------
>>>>> <<<test_start>>>
>>>>> tag=msgctl08 stime=1377689180
>>>>> cmdline="msgctl08"
>>>>> contacts=""
>>>>> analysis=exit
>>>>> initiation_status="ok"
>>>>> <<<test_output>>>
>>>>> ------------->8-------- hung here ------------------
>>>>>
>>>>>
>>>>> Let me know if you need more data/test help.
>>>>>
>>>> Cannot say much to your constellation as I had the issue on x86-64 and
>>>> Linux-next.
>>>> But I have just seen a post-v3.11-rc7 IPC-fix in [1].
>>>>
>>>> I have here a v3.11-rc7 kernel with drm-intel-nightly on top... did not run LTP.
>>>
>>> Not sure what you mean - I'd posted that Im seeing the issue on ARC Linux (an FPGA
>>> board) 3.11-rc7 as well as linux-next of yesterday.
>>>
>>
>> I am not saying there is no issue, but I have no possibility to test
>> for ARC arch.
>>
>>>> Which LTP release do you use?
>>>
>>> The LTP build I generally use is from a 2007 based sources (lazy me). However I
>>> knew this would come up so before posting, I'd built the latest from buildroot and
>>> ran the msgctl08 from there standalone and it did the same thing.
>>>
>>
>> Try always latest LTP-stable (03-May-2013 is what I tried). AFAICS a
>> new release is planned soon.
>>
>>>> Might be good to attach your kernel-config for followers?
>>>
>>> It was already there in my orig msg - you probably missed it.
>>>
>>
>> I have got that response from you only :-).
>>
>>>> [1] http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=368ae537e056acd3f751fa276f48423f06803922
>>>
>>> I tried linux-next of today, same deal - msgctl08 still hangs.
>>>
>>
>> That above fix [1] in Linus-tree is also in next-20130828.
>>
>> Hope Davidlohr and fellows can help you.
>>
>> - Sedat -
>>
>

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