Re: [Rosegarden-user] 21.12 "Cloud Nine" segfaults on Sue-Leap-15.4

2023-05-17 Thread Ted Felix

On 5/16/23 7:09 PM, krsg...@trixtar.org wrote:

# uname -a
Linux localhost.localdomain 6.2.10-1-default #1 SMP PREEMPT_DYNAMIC Thu Apr  6 
10:36:55 UTC 2023 (ba7816e) x86_64 x86_64 x86_64 GNU/Linux


  This is the first time I've seen PREEMPT_DYNAMIC.  That is workable 
so long as preempt is enabled in grub.  To check:


  $ grep -i preempt /etc/default/grub

You should either see nothing or "preempt=full" along with possibly 
other options.



# grep ^CONFIG_HZ /boot/config-`uname -r`
CONFIG_HZ_250=y
CONFIG_HZ=250

So does this mean that I do have a low-latency but not real-time kernel?


  Low-latency (so long as it is configured properly via grub) and a 
low-resolution timer which can lead to timing problems for music. 
Overall, I would characterize this as a partially real-time kernel.


  Might be worth digging around in OpenSUSE to see what other kernel 
packages there are.  Looks like there may be no official kernel-rt 
package anymore, but maybe a community package?


  https://software.opensuse.org/package/kernel-rt


The issue raised is encountered in Suse-Leap.
Rosegarden ran fine before so I presume all the
configs WERE correct at one time, but usually
after a number of upgrades the segfaults begin,
there is no crash, just no takeoff even.


  Ok.  This is odd.  Usually things become *more* stable over time.  Or 
at least stay the same.



Thanks for the ref, the second half is way over
my head but I'll keep it for re-reading.


  Yeah, it's pretty heavy stuff.  And again, it oftentimes leads to the 
discovery that "not much can be done".


Ted.


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Re: [Rosegarden-user] 21.12 "Cloud Nine" segfaults on Sue-Leap-15.4

2023-05-16 Thread krsgrdn
Tue, 16 May 2023 10:34:49 -0400
Ted Felix  :

>There are three issues here.  Two are unrelated to the crash, but 
> I'll walk through them in case you want to fix them.
> 
>  > Cannot lock down 86611866 byte memory area (Cannot allocate memory)
>  > Cannot use real-time scheduling (RR/5)(1: Operation not permitted)
>  > JackClient::AcquireSelfRealTime error
> 
>This indicates that you don't have permissions configured so that 
> JACK can run in real-time and lock down fixed memory areas to do its 
> job.  This isn't likely to be the cause of the crash you are 
> experiencing.  More likely it would cause audio glitches.  I have a 
> webpage that addresses this issue if you are interested in understanding 
> and fixing it:
> 
> http://tedfelix.com/linux/linux-midi.html

Thanks a gig for the detailed response.


# uname -a
Linux localhost.localdomain 6.2.10-1-default #1 SMP PREEMPT_DYNAMIC Thu Apr  6 
10:36:55 UTC 2023 (ba7816e) x86_64 x86_64 x86_64 GNU/Linux

>  > [AlsaDriver] setCurrentTimer(): WARNING: using system timer with only 
>   > 250 Hz resolution!
> 
>This indicates that you are not running with a real-time kernel. 
> This can lead to latency and timing issues, but like the above, it's not 
> likely to cause a crash.  Again, my webpage above explains how to solve 
> this issue.

# grep ^CONFIG_HZ /boot/config-`uname -r`
CONFIG_HZ_250=y
CONFIG_HZ=250

So does this mean that I do have a low-latency but not real-time kernel?

The issue raised is encountered in Suse-Leap.
Rosegarden ran fine before so I presume all the 
configs WERE correct at one time, but usually 
after a number of upgrades the segfaults begin,
there is no crash, just no takeoff even.

Thanks for the ref, the second half is way over 
my head but I'll keep it for re-reading. Leap-15.5 
is out in a few weeks, a fresh install or upgrade 
might do the trick. It will be the last 'Leap' 
as it has been known.

  


 
>  > Segmentation fault (core dumped)
> 
>(Aside: It looks like you are running 22.12 which has a known crash. 
> However, it is a solid crash that would happen every time you launch 
> Rosegarden.  If yours is crashing only occasionally, you aren't 
> experiencing the known crash.)
> 
>This "Segmentation fault" is the real problem at hand and will 
> require some work to figure out.  Not sure how far you want to dig into 
> this.  Oftentimes it is the result of parts of your system that 
> Rosegarden depends on and there may be little you can do without 
> manually building and upgrading things.  It can definitely get ugly.
> 
>If you want to start digging into this one, you'll first need a debug 
> build of Rosegarden.  I think SUSE is one of the distros that (oddly) 
> ships Rosegarden built in debug mode.  That's good for figuring out 
> these sorts of issues.  (Bad for normal use, though.)
> 
>You'll need to find the core dump that was created when Rosegarden 
> crashed.  It's usually called core.#, where "#" is the process 
> ID.  If all is right with the world you can get a backtrace from gdb 
> using its "bt" command like this:
> 
> $ gdb rosegarden core.#
> (gdb) bt
> 
>You may need to track down the path for rosegarden and the core dump. 
>   You may also need to turn core dumps on (sometimes they are disabled 
> because they are huge and can fill your drive).
> 
>There's some old documentation on the wiki related to this:
> 
> https://www.rosegardenmusic.com/wiki/frequently_asked_questions?s[]=%2Agdb%2A#compilation_or_installation_problems
> 
>Let me know if you need more assistance.
> 
> Ted.
> 
> 
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Re: [Rosegarden-user] 21.12 "Cloud Nine" segfaults on Sue-Leap-15.4

2023-05-16 Thread Ted Felix
  There are three issues here.  Two are unrelated to the crash, but 
I'll walk through them in case you want to fix them.


> Cannot lock down 86611866 byte memory area (Cannot allocate memory)
> Cannot use real-time scheduling (RR/5)(1: Operation not permitted)
> JackClient::AcquireSelfRealTime error

  This indicates that you don't have permissions configured so that 
JACK can run in real-time and lock down fixed memory areas to do its 
job.  This isn't likely to be the cause of the crash you are 
experiencing.  More likely it would cause audio glitches.  I have a 
webpage that addresses this issue if you are interested in understanding 
and fixing it:


http://tedfelix.com/linux/linux-midi.html

> [AlsaDriver] setCurrentTimer(): WARNING: using system timer with only 
 > 250 Hz resolution!


  This indicates that you are not running with a real-time kernel. 
This can lead to latency and timing issues, but like the above, it's not 
likely to cause a crash.  Again, my webpage above explains how to solve 
this issue.


> Segmentation fault (core dumped)

  (Aside: It looks like you are running 22.12 which has a known crash. 
However, it is a solid crash that would happen every time you launch 
Rosegarden.  If yours is crashing only occasionally, you aren't 
experiencing the known crash.)


  This "Segmentation fault" is the real problem at hand and will 
require some work to figure out.  Not sure how far you want to dig into 
this.  Oftentimes it is the result of parts of your system that 
Rosegarden depends on and there may be little you can do without 
manually building and upgrading things.  It can definitely get ugly.


  If you want to start digging into this one, you'll first need a debug 
build of Rosegarden.  I think SUSE is one of the distros that (oddly) 
ships Rosegarden built in debug mode.  That's good for figuring out 
these sorts of issues.  (Bad for normal use, though.)


  You'll need to find the core dump that was created when Rosegarden 
crashed.  It's usually called core.#, where "#" is the process 
ID.  If all is right with the world you can get a backtrace from gdb 
using its "bt" command like this:


$ gdb rosegarden core.#
(gdb) bt

  You may need to track down the path for rosegarden and the core dump. 
 You may also need to turn core dumps on (sometimes they are disabled 
because they are huge and can fill your drive).


  There's some old documentation on the wiki related to this:

https://www.rosegardenmusic.com/wiki/frequently_asked_questions?s[]=%2Agdb%2A#compilation_or_installation_problems

  Let me know if you need more assistance.

Ted.


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[Rosegarden-user] 21.12 "Cloud Nine" segfaults on Sue-Leap-15.4

2023-05-15 Thread krsgrdn


I've raised this issue on the Suse mailing list but have been unable to resolve 
it. It has been happening on and off over the years with Suse and with vaguely 
similar error messages, the last two (one right after the other) being:


~ # rosegarden
Cannot lock down 86611866 byte memory area (Cannot allocate memory)
Cannot use real-time scheduling (RR/5)(1: Operation not permitted)
JackClient::AcquireSelfRealTime error
[AlsaDriver] setCurrentTimer(): WARNING: using system timer with only  250 Hz 
resolution!
Segmentation fault (core dumped)
~ # rosegarden
Cannot connect to server socket err = Connection refused
Cannot connect to server request channel
jackdmp 1.9.12
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2016 Grame.
Copyright 2016-2017 Filipe Coelho.
jackdmp comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
Cannot create RT messagebuffer thread: Operation not permitted (1)
Retrying messagebuffer thread without RT scheduling
Messagebuffer not realtime; consider enabling RT scheduling for user
no message buffer overruns
Cannot create RT messagebuffer thread: Operation not permitted (1)
Retrying messagebuffer thread without RT scheduling
Messagebuffer not realtime; consider enabling RT scheduling for user
no message buffer overruns
Cannot create RT messagebuffer thread: Operation not permitted (1)
Retrying messagebuffer thread without RT scheduling
Messagebuffer not realtime; consider enabling RT scheduling for user
no message buffer overruns
JACK server starting in realtime mode with priority 10
self-connect-mode is "Don't restrict self connect requests"
Cannot lock down 86611866 byte memory area (Cannot allocate memory)
audio_reservation_init
Acquire audio card Audio0
creating alsa driver ... hw:II|hw:II|1024|2|48000|0|0|nomon|swmeter|-|32bit
configuring for 48000Hz, period = 1024 frames (21.3 ms), buffer = 2 periods
ALSA: final selected sample format for capture: 32bit integer little-endian
ALSA: use 2 periods for capture
ALSA: final selected sample format for playback: 32bit integer little-endian
ALSA: use 2 periods for playback
Cannot use real-time scheduling (RR/10)(1: Operation not permitted)
AcquireSelfRealTime error
Segmentation fault (core dumped)
~ # 








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