Re: 2.6.31.4-rt14 posix message queues problem

[John Kacur]

> From: Joerg Abraham <Joerg.Abraham@xxxxxxxxxxxxxxxxx>
> Date: Thu, Oct 15, 2009 at 7:51 PM
> Subject: 2.6.31.4-rt14 posix message queues problem
> To: LKML <linux-kernel@xxxxxxxxxxxxxxx>
> 
> 
> Hi,
> 
> During some performance measurement I stumbled over unexpected bad
> results for a posix message queue test case. Which is not surprising
> since the kernel log shows a "BUG: scheduling while atomic:" on every
> measurement trigger.
> 
> Attached is the kernel log for an embedded 8572ds powerpc system and a
> condensed user space test appli. The test appli uses 2 processes
> (mq_server and mq_client) and pingpongs some messages via posix
> message queues. Please see the c-file header for details (the appli
> itself makes not much sense but shows the problem).
> 
> ./mq_server
> ./mq_client # just crashes during run
> 
> The problem does _not_ occur on kernels 2.6.29.6-rt24, 2.6.29.6
> vanilla and 2.6.31.4 vanilla. The problem does _also_ show up on an
> embedded x86_64 system and a full featured fc11 x86_64 system running
> a 2.6.31.4-rt14 based kernel, so I dont think it's arch dependent.
> 
> Can anybody reproduce the crash ???
> 
> If you need more info's please let me know.
> 
> [And if I'm doing stupid things just forgive me]
> 
> Thanx
> 
> Joerg

Hello Joerg

Does the following patch solve your problem?