https://bugs.kde.org/show_bug.cgi?id=510734
Bug ID: 510734
Summary: plasmashell and powerdevil crash in libwayland when
plugging and unplugging monitor quickly
Classification: Plasma
Product: plasmashell
Version First 6.4.5
Reported In:
Platform: Fedora RPMs
OS: Linux
Status: REPORTED
Severity: crash
Priority: NOR
Component: generic-crash
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: 1.0
Created attachment 185876
--> https://bugs.kde.org/attachment.cgi?id=185876&action=edit
Output of `wayland-debug -r plasmashell 2>&1 | tee
plasmashell-crash-2025-10-17.txt`
SUMMARY
When I plug and unplug a monitor quickly into my computer, plasmashell and/or
powerdevil can crash with error "not a valid new object id (4278190410),
message data_offer(n)".
STEPS TO REPRODUCE
1. Quickly plug and unplug a display cable before the kernel can finish reading
its EDID information.
I have two monitors, a HDMI cable to a BenQ GL2760H, and a Benfei USBC-to-VGA
adapter (from Amazon, dp/B076X2XS9R, IDK the chipset) to a VX720 CRT with
overridden EDID.
The CRT feeds through a VGA 4-port switch that only allows me to cycle inputs
sequentially, hence when I switch inputs sometimes I connect the CRT to my
computer for a split-second. I noticed this would trigger plasmashell crashes.
OBSERVED RESULT
Background: I found that Linux labels the HDMI port as DP-1, and USB-C alt mode
(to VGA) as DP-2.
If I briefly plug the CRT (which is not enabled) into the DAC and unplug the
VGA side (the DAC remains in the computer), the kernel and kwin can't read the
EDID, plasmashell and/or powerdevil crash.
The exact string (eg. data_offer) can change, I've seen data_offer(n), mode(n),
and (one time) activation(n).
The message "not a valid new object id" appears to come from
wayland#src/connection.c, at
https://gitlab.freedesktop.org/wayland/wayland/-/blob/main/src/connection.c?ref_type=heads#L1023-1025.
This is not KDE-specific code, but I suspect either kwin is generating invalid
messages out of order from a race condition, or plasmashell/powerdevil could be
processing Wayland messages incorrectly? In any case I was told to post this
bug to plasmashell.
I may be able to debug the code control flow further in the future, after I've
cloned wayland and set up my IDE.
(Note that Firefox spews messages "Couldn't map window 0x7f758fe46980 as
subsurface" every time you add or remove a screen, even if you let the computer
settle.)
EXPECTED RESULT
No crash.
SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 42
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.19.0
Qt Version: 6.9.2
Kernel Version: 6.16.11-200.fc42.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-8559U CPU @ 2.70GHz
Memory: 16 GiB of RAM (15.5 GiB usable)
Graphics Processor: Intel® Iris® Plus Graphics 655
Manufacturer: Intel(R) Client Systems
Product Name: NUC8i7BEH
System Version: J72992-303
ADDITIONAL INFORMATION
Previously reported as Bug 508917.
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