Re: ipc-msg broken again on 3.11-rc7?

[Vineet Gupta]

On 09/03/2013 02:27 PM, Manfred Spraul wrote:
> On 09/03/2013 10:44 AM, Vineet Gupta wrote:
>>> b) Could you check that it is not just a performance regression?
>>>       Does ./msgctl08 1000 16 hang, too?
>> Nope that doesn't hang. The minimal configuration that hangs reliably is msgctl
>> 50000 2
>>
>> With this config there are 3 processes.
>> ...
>>    555   554 root     S     1208  0.4   0  0.0 ./msgctl08 50000 2
>>    554   551 root     S     1208  0.4   0  0.0 ./msgctl08 50000 2
>>    551   496 root     S     1208  0.4   0  0.0 ./msgctl08 50000 2
>> ...
>>
>> [ARCLinux]$ cat /proc/551/stack
>> [<80aec3c6>] do_wait+0xa02/0xc94
>> [<80aecad2>] SyS_wait4+0x52/0xa4
>> [<80ae24fc>] ret_from_system_call+0x0/0x4
>>
>> [ARCLinux]$ cat /proc/555/stack
>> [<80c2950e>] SyS_msgrcv+0x252/0x420
>> [<80ae24fc>] ret_from_system_call+0x0/0x4
>>
>> [ARCLinux]$ cat /proc/554/stack
>> [<80c28c82>] do_msgsnd+0x116/0x35c
>> [<80ae24fc>] ret_from_system_call+0x0/0x4
>>
>> Is this a case of lost wakeup or some such. I'm running with some more diagnostics
>> and will report soon ...
> What is the output of ipcs -q? Is the queue full or empty when it hangs?
> I.e. do we forget to wake up a receiver or forget to wake up a sender?
/ # ipcs -q

------ Message Queues --------
key        msqid      owner      perms      used-bytes   messages   
0x72d83160 163841     root       600        0            0      


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