[kde] [Bug 327165] New: KDE Apps, workspace elements freezes randomly

[Kopiás Csaba]

https://bugs.kde.org/show_bug.cgi?id=327165

            Bug ID: 327165
           Summary: KDE Apps, workspace elements freezes randomly
    Classification: Unclassified
           Product: kde
           Version: 4.11.2
          Platform: Kubuntu Packages
                OS: Linux
            Status: UNCONFIRMED
          Severity: grave
          Priority: NOR
         Component: general
          Assignee: unassigned-bugs at kde.org
          Reporter: metamorfozis at metamorfozis.hu

Hello!

Since upgrading to Kubuntu 13.10 i'm experiencing random freezes all around the
kde world.
This freezes never touches any non kde app, e.g. chrome, netbeans etc is
working always.

I think the problem lies within some shared module or lib, that locks up
sometimes, as the locks are not always happens the same way and affects the
same way the gui.

At times, the whole plasma-desktop locks up, so no response from the taskbar,
neither alt-f2 neither trigger desktop-grid via screen edge.
But at times only one app freezes (like krusader or systemsettings) and others
are not touched.

What have caused lockups so far? (The following list means, it happened during
this events, but doesn't mean, that it always locks up when i do them)
 * Opening new tab in yakuake
 * Opening systemsettings 
 * Renaming a file in krusader (it freezed before move, and before the gui
textbox would become a normal line again)
 * Messing around plasma widgets
 * Just opening k-menu (i use the classic one)
 * Entering a folder from krusader

I would like to help you in everything to debug this out, you can contact me
directly via email or some im (eg skype) if you want, i would really appreciate
that.

I've tried to mess around with plasma-desktop and strace, but i'm not an expert
in debugging c/c++ apps,
but what i have found two things:
 * Many times it select()-s on something which is never doing anything
seemingly while the gui is frozen
 * Just a few minutes ago i've read a trick about disabling gestures in
#325265, and systemsettings is just decided to not let me do that (freezed
after every event), so i straced that too, and it was stuck at poll/recvmsg.

In detail:
1st case:
meta at x220:~$ ps aux | grep plasma
meta      6272  3.1  2.5 3355504 204080 ?      Sl   23:12   1:00
/usr/bin/plasma-desktop
meta      7457  0.0  0.1 190800 10676 ?        S    23:41   0:00 kdeinit4:
kio_desktop [kdeinit] desktop
local:/tmp/ksocket-meta/klauncherhX7452.slave-socket
local:/tmp/ksocket-meta/plasma-desktopDr6272.slave-socket
meta      7653  0.0  0.0  10940   980 pts/10   S+   23:44   0:00 grep
--color=auto plasma
meta at x220:~$ sudo strace -f 6272
[sudo] password for meta: 
strace: Can't stat '6272': No such file or directory
meta at x220:~$ sudo strace -fp 6272
Process 6272 attached with 5 threads
[pid  7204] select(5, [4], NULL, NULL, NULL <unfinished ...>
[pid  6279] restart_syscall(<... resuming interrupted call ...> <unfinished
...>
[pid  6278] restart_syscall(<... resuming interrupted call ...> <unfinished
...>
[pid  6275] futex(0x7f8eb60c8fd4, FUTEX_WAIT_PRIVATE, 1, NULL <unfinished ...>
[pid  6272] select(30, [29], [], NULL, NULL

And this is where it was for 15minutes, of course being frozen the whole time.

2st case with systemsettings:
[pid 11028] sendmsg(5, 0x7fff04693a50, MSG_NOSIGNAL) = 161
[pid 11028] poll([?] 0x7fff04693b30, 1, 25000) = 1
[pid 11028] recvmsg(5, 0x7fff04693a30, MSG_CMSG_CLOEXEC) = 89
[pid 11028] recvmsg(5, 0x7fff04693a30, MSG_CMSG_CLOEXEC) = -1 EAGAIN (Resource
temporarily unavailable)
[pid 11028] sendmsg(5, 0x7fff04693c50, MSG_NOSIGNAL) = 128
[pid 11028] poll([?] 0x7fff04693d30, 1, 25000


I didn't wanted to attach a full strace because i'm not really sure what
process i should trace, and that it might contain non public information.
So if you would help me, to make any debug output that is filtered as much as
possible, then i will share that.
for example it would be good to know what file that they were polling... but i
don't know how to extract that.
And i assume, kde has a lot of debugging tools.

So, thank you very much, i'm looking forward to help you debug this nasty one.
Nasty because of course it disturbs the user, and nasty as it is random and not
easily reproducible.

Meta






Reproducible: Sometimes

Steps to Reproduce:
I've described a few scenarios above.
Actual Results:  
Freezing,  and no response either from just the app, or either from the whole
kde stack.
But non KDE apps are never struggles with this.

Expected Results:  
Seamless responses:)

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