Bug 400534

Summary: Flash in Firefox in fullscreen mode breaks plasmashell/KWin
Product: [Plasma] plasmashell Reporter: pemartins <paulo76.algarve>
Component: generic-crashAssignee: Plasma Bugs List <plasma-bugs-null>
Status: RESOLVED NOT A BUG    
Severity: normal CC: kde
Priority: NOR    
Version First Reported In: 5.14.2   
Target Milestone: 1.0   
Platform: Neon   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description pemartins 2018-11-01 00:02:42 UTC 
SUMMARY
Flash in Firefox in full screen breaks plasmashell/Kwin, every time I put a flash video stream in full screen mode the plasmashell crashes (but no crash report is generated by the system).
In order to get things working again I have to close the Firefox tab that has the flash video and run the commands:
killall plasmashell && kwin && plasmashell &

STEPS TO REPRODUCE
1. In Firefox browser go to a website that has a flash video, in example:
https://student.testmasters.com/portal/online/Test.aspx
2. When the video starts, put it in fullscreen mode.
3. Plasmashell/KWin should crash right away

OBSERVED RESULT
plasmashell/Kwin crashing

EXPECTED RESULT
plasmashell/Kwin not to crash

SOFTWARE VERSIONS
System:    Host: pemartins-X55U Kernel: 4.15.0-38-generic x86_64 bits: 64 Desktop: KDE Plasma 5.14.2
        Distro: KDE neon User Edition 5.14
Machine:   Device: laptop System: ASUSTeK product: X55U v: 1.0 serial: N/A
        Mobo: ASUSTeK model: X55U v: 1.0 serial: N/A
        UEFI: American Megatrends v: X55U.423 date: 08/06/2013
CPU:       Dual core AMD E2-1800 APU with Radeon HD Graphics (-MCP-) cache: 512 KB
        clock speeds: max: 1700 MHz 1: 871 MHz 2: 872 MHz
Graphics:  Card: Advanced Micro Devices [AMD/ATI] Wrestler [Radeon HD 7340]
        Display Server: x11 (X.Org 1.19.6 ) drivers: ati,radeon (unloaded: modesetting,fbdev,vesa)
        Resolution: 1366x768@60.01hz
        OpenGL: renderer: AMD PALM (DRM 2.50.0 / 4.15.0-38-generic, LLVM 6.0.0) version: 3.3 Mesa 18.0.5
Audio:     Card-1 Advanced Micro Devices [AMD] FCH Azalia Controller driver: snd_hda_intel
        Card-2 Advanced Micro Devices [AMD/ATI] Wrestler HDMI Audio driver: snd_hda_intel
        Sound: Advanced Linux Sound Architecture v: k4.15.0-38-generic
Network:   Card-1: Ralink RT5390 Wireless 802.11n 1T/1R PCIe driver: rt2800pci
        IF: wlp1s0 state: up mac: <filter>
        Card-2: Qualcomm Atheros AR8161 Gigabit Ethernet driver: alx
        IF: enp2s0 state: down mac: <filter>
Drives:    HDD Total Size: 500.1GB (8.5% used)
        ID-1: /dev/sda model: ST500LM012_HN size: 500.1GB
Partition: ID-1: / size: 97G used: 37G (40%) fs: ext4 dev: /dev/sda5
        ID-2: swap-1 size: 3.85GB used: 0.00GB (0%) fs: swap dev: /dev/sda6
RAID:      No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors:   System Temperatures: cpu: 59.0C mobo: N/A gpu: 59.0
        Fan Speeds (in rpm): cpu: 3100
Info:      Processes: 164 Uptime: 35 min Memory: 1310.0/3528.9MB Client: Shell (xterm) inxi: 2.3.56

ADDITIONAL INFORMATION
I'm using the latest Firefox version Firefox Quantum 63.0 (64-bit).
Comment 1 David Edmundson 2018-11-01 12:28:49 UTC 
Doesn't crash here.

Please include a backtrace.
Comment 2 pemartins 2018-11-01 16:20:45 UTC 
Thank you for your feedback David.

Can you point me to a place where I can learn how to do a backtrace? I do not know what it is.
Comment 3 pemartins 2018-11-01 19:43:29 UTC 
I was able to fix this by installing flash player in a different way. At first flash was installed as
sudo apt install flashplugin-installer

but for some reason the crash happened every time even after reinstall. But installing flash as
sudo apt install adobe-flashplugin browser-plugin-freshplayer-pepperflash

solves the issue and flash video in full screen mode no longer crashes plasmashell or KWin.
Comment 4 pemartins 2018-11-02 02:32:55 UTC 
Actually some flash player streams in full screen still break at least KWin. Please let me know how to do a backtrace so I can provide the information.
Comment 6 pemartins 2018-11-02 23:55:49 UTC 
Thank you Christoph for the help.

Unfortunately I cannot get a backtrace report, it does not appear automatically and I wasn't able to get one with gdb either.

Installed kdelibs5-dbg and firefox-dbg but no luck, running gdb kwin or gdb plasmashell also no luck.

One of the things that happens is that the toolbars of the windows disappear which means that kwin crashed (right) but I cannot get a report.

I'll try again when possible but for now just close the thread.
Thank you all for your help.
Comment 7 Christoph Feck 2018-11-03 21:12:16 UTC 
Try:

gdb --args kwin_x11 --replace
(gdb) run
[-- use kwin, wait for crash --]
(gdb) thread apply all bt
[-- press Enter multiple times, pastebin all output --]
Comment 8 pemartins 2018-11-04 20:06:26 UTC 
Thank you very much once again Christoph for your help.

So now that with your instructions I was able to generate a backtrace report, KWin never crashed again... It always has hiccups when flash comes out of fullscreen but the crashes stopped, only a couple of seconds freezes occur every time.

I changed some things yesterday, in example I changed the cursor theme among other things, so probably something I changed had some collateral effect.
Also after my last post I realized that mpv media player also always crashed KWin if I put it on fullscreen, but also it is not happening anymore. Only 'hiccups' just like in flash.

Here is a gdb report in which I ran mpv and flash in firefox:
https://pastebin.com/raw/P1jZNMRa
Comment 9 pemartins 2018-11-17 21:50:05 UTC 
I had to reinstall the system and it did not happen again, all is working as expected now.
As far as I can tell it was an isolated incident and not a bug.