Bug 400585 - plasmashell process consumes all shared memory (SHM) segments, causing problems for other process that need to be able to allocate SHM
Summary: plasmashell process consumes all shared memory (SHM) segments, causing proble...
Status: RESOLVED FIXED
Alias: None
Product: plasmashell
Classification: Plasma
Component: general (show other bugs)
Version: 5.14.2
Platform: Kubuntu Linux
: NOR normal
Target Milestone: 1.0
Assignee: David Edmundson
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2018-11-02 11:30 UTC by Cobus Carstens
Modified: 2019-09-06 08:23 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
Output of lsipc -m. Notice all the plasmashell entries. (389.65 KB, text/plain)
2018-11-02 11:30 UTC, Cobus Carstens
Details

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Description Cobus Carstens 2018-11-02 11:30:02 UTC
Created attachment 116046 [details]
Output of lsipc -m. Notice all the plasmashell entries.

SUMMARY
Shortly after system boot all available shared memory segments are consumed by the plasmashell process, causing other applications that makes use of it (for rendering, for instance) to fail [in my case specifically the `keepassx` application].

STEPS TO REPRODUCE
1. Boot
2. Check shared memory using the `lsipc` command.
3. Repeat 2 and watch the shared memory segments usage climb to 100%

OBSERVED RESULT

From `lsipc`:
SHMMNI   Shared memory segments                                    4096   4096 100.00%
SHMALL   Shared memory pages                       18446744073692774399 575743   0.00%
SHMMAX   Max size of shared memory segment (bytes) 18446744073692774399      -       -

From `lsipc -m`:
0x00000000 196055039 rwxrwxrwx   cobusc 480K      1 dest   Nov01 6380 19719 /usr/bin/plasmashell
(this is repeated 4072 times) notice that the segments are flagged as "to be destroyed", but it cannot, since the process is still attached.




EXPECTED RESULT


SOFTWARE VERSIONS
(available in About System)
KDE Plasma Version: 4:5.14.2-0ubuntu1~ubuntu18.10~ppa1
KDE Frameworks Version: 5.51.0
Qt Version: 5.11.1

ADDITIONAL INFORMATION
Comment 1 David Edmundson 2018-11-02 12:55:46 UTC
Please report if:
* it happens under a new user / wiped ~/.config/plasma*
* Run kcmshell5 qtquicksettings and report with the software backend
Comment 2 Cobus Carstens 2018-11-02 14:19:15 UTC
It does not occur for a new user.
Also, removing ~/.config/plasma* fixed it for the existing user.

Thanks! Marking as resolved.
Comment 3 Cobus Carstens 2018-11-05 10:06:30 UTC
I seem to have been a bit premature in marking the issue as resolved.
The issue re-surfaced after deleting ~/.config/plasma*

Using the software rendered seems to do the trick. I have been working for a few hours now and the SHM is constant.
Comment 4 Cobus Carstens 2018-11-14 06:49:48 UTC
Removing the Nouveau drivers and using the Intel ones seems to have sorted out the problem.