RTEMS 5.1 pc686 BSP malloc_info problem?

Alan Cudmore alan.cudmore at gmail.com
Mon Oct 5 16:07:00 UTC 2020


I built the tools shortly after the announced 5.1 release. I'm using
the 5.1 branches for everything.
But some additional info..I built the full testsuite, and ran the
malloctest with no problems. It calls malloc_info a couple of times.

I also compiled my RTEMS Kernel Image (RKI) for this BSP and the
"malloc info" shell command works on that. This is the same way I
tested the sparc/leon3 BSP so at least that is consistent.

This has to come down to a configuration issue for the application
(core flight system pc-rtems test platform)
I'm going to check over the configuration options and compiler options
used. It will most likely be another case of user error, which I
prefer!

Thanks,
Alan

On Mon, Oct 5, 2020 at 11:58 AM Joel Sherrill <joel at rtems.org> wrote:
>
>
>
> On Mon, Oct 5, 2020 at 10:34 AM Gedare Bloom <gedare at rtems.org> wrote:
>>
>> This is an SMP related bug?  Can you send the rtems configure command,
>> and the qemu run command?
>>
>> It might also help to know the number of tasks and their priorities.
>> The CONFIGURE* macros might also help.
>>
>> My first guess is that the lock primitive is somehow broken in the
>> pc686, maybe it gets caught in a buggy CAS/TAS loop? It would help if
>> you can narrow down the task spinning to a particular section of code
>> and send the disassembly (or file/line if it is in RTEMS)
>
>
> Hmmm.. When did you build your i386 tools? git says 9/19 for the last change
> but it was very much likely a few days after that when I pushed it.
>
> --joel
>>
>>
>> On Sun, Oct 4, 2020 at 2:06 PM Alan Cudmore <alan.cudmore at gmail.com> wrote:
>> >
>> > Hi,
>> > I have a problem in RTEMS 5.1 where the pc686 running on QEMU seems to
>> > block or spin when trying to acquire a lock for the malloc_info call.
>> > The CPU utilization goes up to 100 (on the QEMU host) leading me to
>> > think the calling task is spinning waiting on the lock. Tasks with
>> > lower priority than the calling task stop running as well. I also get
>> > this problem when running the "malloc info" shell command.
>> > I don't see this problem with the leon3 BSP built from the same source
>> > tree and executed on QEMU.
>> >
>> > Is there an SMP related initialization or perhaps QEMU option I might
>> > be missing? I can run the same code without problems on the RTEMS 4.11
>> > release (same QEMU binary and QEMU options)
>> >
>> > Thanks,
>> > Alan
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