lxpanel freezes when many programs are open and lxpanel is being used

Bug #800297 reported by Mathilda Young on 2011-06-21
This bug affects 9 people
Affects Status Importance Assigned to Milestone
lxpanel (Ubuntu)

Bug Description

Binary package hint: lxpanel

I was running LibreOffice, Chromium, and PCManFM when lxpanel froze. I was trying to launch the application menu when lxpanel crashed.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: lxpanel 0.5.6-1ubuntu4
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic
Uname: Linux 2.6.38-8-generic i686
Architecture: i386
 FileManager=pcmanfm %s
 Terminal=lxterminal -e
Date: Tue Jun 21 12:03:14 2011
InstallationMedia: Lubuntu 11.04 "Natty Narwhal" - i386 (20101203)
SourcePackage: lxpanel
UpgradeStatus: No upgrade log present (probably fresh install)

Mathilda Young (gtrsdk) wrote :
IKT (ikt) wrote :

This is also affecting me, happens randomly.

Changed in lxpanel (Ubuntu):
status: New → Confirmed
Emilio (emilio-moretti) wrote :

Same problem here. I was using Firefox 5, several LibreOffice windows and PCManFM. I had to manually kill and restart the panel from a terminal.

Emilio (emilio-moretti) wrote :

ok, this is really easy to reproduce:
Open eight LibreOffice windows and one PCManFM window. Now try to close several LibreOffice windows doing "Right click -> Close" in the lxpanel.

That's it. The panel freezes and you have to open a new terminal window to close it and open a new instance.

Emilio (emilio-moretti) wrote :

I compiled and updated lxpanel to 0.5.8 in my box and the issue has been fixed. Or at least I couldn't reproduce it anymore.

I had to install libgtk2.0-dev, libmenu-cache1-dev and intltool packages in order to compile it, but it was worth the hassle.

For those affected by this:
*Install the following packages
sudo apt-get install libgtk2.0-dev libmenu-cache1-dev intltool

Download lxpanel source from

Compile it and install it:
./configure --prefix=/usr
sudo make install

Log out and log in again.

Emilio (emilio-moretti) wrote :

I reproduced the issue again running lxpanel 0.5.8

Schelling (raulschelling) wrote :

It happens to me too in Lubuntu 11.04 and now in 11.10, but it seems that it is the combination of Libreoffice and Taskbar in Lxpanel. I just unable the taskbar (windows list) and it seems to be working fine. Maybe the developers didn't see this because Abiword is the program by default.

Croque (pcroque) wrote :

I am getting random lxpanel freezes too (lubuntu 11.10 using latest libreoffice in the repos). Not sure if it's related but I sometimes get the following error in the terminal that started lxpanel when I close libreoffice writer:..."lxpanel : X error: BadWindow (invalid Window parameter)" even though lxpanel continues to respond.

Jeroen Tietema (jtietema) wrote :

I am having frequent freezes of lxpanel when only using chromium browser. I don't have LibreOffice. Running "lxpanelctl restart" from the console seems to fix the freeze.

massimoi (massimoi) wrote :

I've installed LXDE (in Lubuntu) on a lot of PC, and all of them report random freezes of lxpanel (it seems connected to intense use of Libreoffice).

The panel gets to 100% cpu, no way to stop it (via lxpanelctrl), just kill and re-launch (not easy for my users!).

Any help apreciated,

jean-baptiste (jbateau54) wrote :

same here (on 2 différent computer), but on Archlinux. So it is not an ubuntu related bug and the 5.8 version don't solve anything. I don't know if it's libreoffice related but i observe that it happen mostly when the task list is full.
To reboot easily, it make crtl+alt+supp to launch "lxtash", i target "lxpanel" an i select "end" which make "lxpanel" reboot.
have a nice day

Gordon Dracup (gordon-dracup) wrote :

Same issue here on Lubuntu 11.10, although it happens when I use Thunderbird, not LibreOffice. Not sure if this is significant

Gordon Dracup (gordon-dracup) wrote :

"lxpanelctl restart" does not work for me. There seems to be numerous references the this issue on the web. Is there any chance that it could be allocated? Happy to provide information to help getting this resolved.

Guntbert Reiter (guntbert) wrote :

workaround: in terminal type
killall lxpanel; lxpanel --profile Lubuntu &
(helps against the "growing notification area" too...)

Peter Gervai (grin) wrote :

task state when frozen:

stack:[<c102fa76>] enqueue_task_rt+0x1a6/0x1c5
stack:[<c102ac3d>] test_tsk_need_resched+0xa/0x13
stack:[<c102dc06>] resched_task+0x30/0x57
stack:[<c102ac3d>] test_tsk_need_resched+0xa/0x13
stack:[<c102e54a>] check_preempt_curr+0x48/0x58
stack:[<c107b514>] rcu_enter_nohz+0xc/0x55
stack:[<c103d00d>] irq_exit+0x5d/0x80
stack:[<c100cd96>] do_IRQ+0x65/0x76
stack:[<c12b971a>] work_resched+0x5/0x20
stack:[<c12b0000>] amd_64_threshold_cpu_callback+0xbb/0x22b
stack:[<ffffffff>] 0xffffffff
stat:26983 (lxpanel) R 1 26983 17542 0 -1 4202496 127554 249 273 1 103527 5501 0 0 20 0 1 0 151461212 170442752 3164 4294967295 134512640 134705020 3217543024 3217541708 3068874055 0 0 4096 0 0 0 0 17 0 0 0 817 0 0
statm:41612 3164 1781 47 0 1305 0
status:Name: lxpanel
status:State: R (running)
status:Tgid: 26983
status:Pid: 26983
status:PPid: 1
status:TracerPid: 0
status:Uid: 1000 1000 1000 1000
status:Gid: 1000 1000 1000 1000
status:FDSize: 256
status:Groups: 6 7 20 22 24 25 29 40 44 46 50 60 107 116 151 154 156 168 171 185 1000 1014 1019 1029 1030
status:VmPeak: 167136 kB
status:VmSize: 166448 kB
status:VmLck: 0 kB
status:VmPin: 0 kB
status:VmHWM: 16628 kB
status:VmRSS: 12656 kB
status:VmData: 5084 kB
status:VmStk: 136 kB
status:VmExe: 188 kB
status:VmLib: 17720 kB
status:VmPTE: 308 kB
status:VmSwap: 0 kB
status:Threads: 1
status:SigQ: 6/64286
status:SigPnd: 0000000000000000
status:ShdPnd: 0000000000000000
status:SigBlk: 0000000000000000
status:SigIgn: 0000000000001000
status:SigCgt: 0000000180000000
status:CapInh: 0000000000000000
status:CapPrm: 0000000000000000
status:CapEff: 0000000000000000
status:CapBnd: ffffffffffffffff
status:Cpus_allowed: ffff
status:Cpus_allowed_list: 0-15
status:Mems_allowed: 1
status:Mems_allowed_list: 0
status:voluntary_ctxt_switches: 1685535
status:nonvoluntary_ctxt_switches: 78354

stack:[<c12ba99e>] nmi_handle.isra.0+0x2f/0x4a
stack:[<c107b514>] rcu_enter_nohz+0xc/0x55
stack:[<c103d00d>] irq_exit+0x5d/0x80
stack:[<c100cd96>] do_IRQ+0x65/0x76
stack:[<c12b971a>] work_resched+0x5/0x20
stack:[<c12b0000>] amd_64_threshold_cpu_callback+0xbb/0x22b
stack:[<ffffffff>] 0xffffffff

nigel hinton (nigelbhinton) wrote :

I've just installed Lubuntu after some troublesome experiences with Ubuntu (Wine not working with essential legacy app, dvb-tv not working after hours of research after upgrade etc). Like Lubuntu a lot but I'm getting the LibreOffice freeze every day now and I've just lost a hours' work due to corrupt file. (Forgot to set auto backup in my new install).

The point is that this is now a show-stopper for me as I've learned that using terminal based 'fixes' is a no-no. Is there an OFFICIAL fix for this ? I'm trying to find out how to install FLuxbox which I've used before and like - is there anyone who uses Fluxbox and LibreOffice regularly who can affirm that it works OK?

I only use 3-4 spreadsheets at a time and believe that it has occurred when only a single worksheet has been up but I had been working in and out of several - not particularly demanding usage pattern.

Can't believe that this issue is still 'in the air' as it is a fundamental problem and perhaps it should have visibility for those contemplating using Lubuntu with Libre Office.

Tried to install OpenOffice to see if that work OK but can't get it loaded via Synaptic - will OpenOffice overcome this problem?

As far as Abiword, Gnumeric being the reason that this problem wasn't spotted during testing, I would have thought a lot of users would wish to use either OpenOffice or LibreOffice as a lot of the functionality of these is not present in those basic (but good) apps.

It's easy to recreate - just open a few spreadsheets, do some work and it'll happen.

Emilio (emilio-moretti) wrote :

I can't reproduce this anymore in lxpanel 0.5.10 + LibreOffice 3.5

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