POSIX mq_receive NULL Priority

[Vincent Galbo]

Thanks guys, 

I think I will attempt to patch it myself and remain with this version of
RTEMS. However, I am having trouble actually finding the mqueuerecvsupp.c
files in the RTEMS source. Can you direct on how to locate and compile this
patch into this version of RTEMS? 

Thanks again,
Vincent Galbo

-----Original Message-----
From: Daniel Hellstrom [mailto:daniel at gaisler.com] 
Sent: Monday, March 18, 2013 12:13 PM
To: Joel Sherrill
Cc: Vincent Galbo; rtems-users at rtems.org
Subject: Re: POSIX mq_receive NULL Priority

Hello All,

Joel, thanks for CC:ing me.

The Gaisler RCC has this problem since we're still on 4.10.1. There are a
couple of patches from 4.10.1 to 4.10.2, and I have it on my TODO to update
our RCC release to 4.10.2. Vincent, I will try to find time in the coming
weeks to rebase RCC to 4.10.2, in the meantime you can apply the patch(es)
manually or by using the RCC Git repository and then rebuild the kernel
yourself. If you have further questions about RCC you can mail
support at gaisler.com.

Regards,
Daniel


On 03/18/2013 04:58 PM, Joel Sherrill wrote:
> On 3/18/2013 10:34 AM, Vincent Galbo wrote:
>>
>> Hello,
>>
>> I am not sure if this bug is common knowledge or not, but I figured I
would report my findings.
>>
> I don't know it can be called common  knowledge because I didn't even 
> remember it. :) The logs mention PR 1890 and PR 1895.
>
> But I committed the fix on 2011-08-21 to the head
>
> http://git.rtems.org/rtems/commit/cpukit/posix/src/mqueuerecvsupp.c?id
> =e5ca6593f7c7b543481147ca7f87696ecc821c06
>
> And to the 4.10 branch on 2011-09-01
>
> http://git.rtems.org/rtems/commit/cpukit/posix/src/mqueuerecvsupp.c?h=
> 4.10&id=a1bfb335c0cc274513e144da46e203bff29e000b
>
> Is there a newer Gaisler version? cc'ing Daniel Hellstrom for feedback.
>
> And thank you for reporting this again. This time we got an easy solution.
>
>> I am working with RTEMS-4.10-1.2.7 on a UT699 LEON3. I received my RTEMS
source from http://www.gaisler.com/anonftp/rcc/src/ .
>>
>> I have been using the function mq_receive to pass messages between 
>> POSIX threads (http://linux.die.net/man/3/mq_receive). Many manual 
>> pages explain that the fourth parameter, *msg_prio, can be left NULL 
>> if you do not care about the message priority. During some testing, I
noticed that my mkprom2 boot loader was becoming corrupted. I determined
that the mq_receive call was overriding my memory location 0. This was due
to passing NULL into the priority parameter value. The mq_receive function
must not check for NULL, and places the priority of the received message
into whatever memory location is placed in the msg_prio parameter. My
current work around is to pass in a dummy variable for the priority
parameter.
>>
>> Vincent Galbo
>>
>
>
> -- 
> Joel Sherrill, Ph.D.             Director of Research & Development
> joel.sherrill at OARcorp.com         On-Line Applications Research
> Ask me about RTEMS: a free RTOS  Huntsville AL 35805
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