Bug 457139

Summary:	kwin_wayland crashes in KWin::DrmGpu::~DrmGpu() when plugging in an HDMI monitor
Product:	[Plasma] kwin	Reporter:	Nate Graham <nate>
Component:	platform-drm	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED FIXED
Severity:	crash	CC:	xaver.hugl
Priority:	NOR
Version First Reported In:	master
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Nate Graham 2022-07-25 20:34:22 UTC

All KDE stuff from today's git master.

STEPS TO REPRODUCE
1. Plug HDMI monitor into the HDMI port on my laptop

OBSERVED RESULT
kwin_wayland crashes 100% of the time in KWin::DrmGpu::~DrmGpu():

#0  0x00007f131898ac86 in std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count() (this=0x1365768, __in_chrg=<optimized out>) at /usr/include/c++/12/bits/shared_ptr_base.h:1070
#1  std::__shared_ptr<KWin::ColorTransformation, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr() (this=0x1365760, __in_chrg=<optimized out>) at /usr/include/c++/12/bits/shared_ptr_base.h:1524
#2  std::shared_ptr<KWin::ColorTransformation>::~shared_ptr() (this=0x1365760, __in_chrg=<optimized out>) at /usr/include/c++/12/bits/shared_ptr.h:175
#3  KWin::DrmPipeline::State::~State() (this=0x1365728, __in_chrg=<optimized out>) at /home/nate/kde/src/kwin/src/backends/drm/drm_pipeline.h:169
#4  KWin::DrmPipeline::~DrmPipeline() (this=0x1365600, __in_chrg=<optimized out>) at /home/nate/kde/src/kwin/src/backends/drm/drm_pipeline.cpp:47
#5  0x00000000011ff8e0 in  ()
#6  0x00000000011df7e8 in  ()
#7  0x00007f131509d143 in __GI___libc_free (mem=0x1365600) at malloc.c:3376
#8  0x00007f1318974bcd in KWin::DrmGpu::~DrmGpu() (this=0x11df7f8, __in_chrg=<optimized out>) at /home/nate/kde/src/kwin/src/backends/drm/drm_gpu.cpp:135
#9  0x0000000000000000 in  ()

This is 100% reproducible for me.

Comment 1 Zamundaaa 2022-07-25 22:11:41 UTC

This doesn't look right - it's jumping from destroying the gbm_device to some code inside KWin... we had a use after free recently (bug 457002), that may be related.
Can you try running KWin with valgrind?

Comment 2 Nate Graham 2022-07-25 22:44:16 UTC

Sure but won't I lose everything once kwin_wayland crashes? How would that work?

Comment 3 Zamundaaa 2022-07-26 07:26:55 UTC

you can run it from a tty instead of a running session. Something like
> dbus-run-session valgrind kwin_wayland plasmashell
should work

Comment 4 Nate Graham 2022-08-11 15:52:01 UTC

I can't reproduce this bug anymore. I guess it got fixed since I filed it.