Hello Santos, I tried to reproduce this issue but did not see it inside a minimal VM. Therefore tried to some more information from the Code bytes printed in you journal/dmesg.
This should point to this instruction: 0x00007f6e16bd5268 <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+24>: 49 8b 87 c8 00 00 00 mov 0xc8(%r15),%rax A breakpoint set to this instruction points to this source line: 0x...268 in QListData::isEmpty() const at /usr/include/x86_64-linux-gnu/qt5/QtCore/qlist.h:116 The unmangled function name should read like this: KWaylandServer::SurfaceInterface::frameRendered(unsigned int) Unfortunately this seems not exact enough to take further actions. Therefore I would suggest installing, if possible, the package systemd-coredump. That way in the journal a simple backtrace should be printed which might give an idea which functions are involved. (As there may crash multiple processes as the wayland server dies, make sure to get the lines after this line: "Process ... (kwin_wayland) of user ... dumped core" On the other side a search in upstream bugtracker returned [1]. I could immediately reproduce that crash by dragging an icon from the kickoff menu onto a opened konsole window, which crashed in the exact same instruction, pointed to by the code bytes from the bug submission. Therefore I guess chances are not too bad this bug is related. Kind regards, Bernhard [1] https://bugs.kde.org/show_bug.cgi?id=428399
# single-use Bullseye/testing amd64 qemu VM 2021-03-29 echo "set enable-bracketed-paste off" >> /etc/inputrc; bash apt update # to speedup testing mv /etc/manpath.config /etc/manpath.config.renamed apt install libeatmydata1 export LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libeatmydata.so apt dist-upgrade apt install systemd-coredump mc gdb rr valgrind sddm plasma-workspace-wayland dolphin konsole lilypond-doc-html \ libkwaylandserver5-dbgsym apt build-dep libkwaylandserver5 mkdir /home/benutzer/source/libkwaylandserver5/orig -p cd /home/benutzer/source/libkwaylandserver5/orig apt source libkwaylandserver5 cd cp -a /usr/share/doc/lilypond/html/Documentation/58/lily-ab77784d.ly . # could not reproduce by drag and drop ... https://wiki.debian.org/InterpretingKernelOutputAtProcessCrash # By bug submitter: kernel: kwin_wayland[12033]: segfault at e8 ip 00007fbbe21d5268 sp 00007ffe4b5000b0 error 4 in libKWaylandServer.so.5.20.5[7fbbe217d000+b6000] kernel: Code: 00 00 48 8b 47 10 48 8b 40 48 c3 90 66 0f 1f 44 00 00 41 57 41 56 41 55 41 54 41 89 f4 55 48 89 fd 53 48 83 ec 18 4c 8b 7f 10 <49> 8b 87 c8 00 00 00 8b 48 0c 8b 58 08 89 4c 24 0c 89 5c 24 08 39 error 4 == 0b100 0: no page found 0: read access 1: user-mode access echo -n "find /b ..., ..., 0x" && \ echo "00 00 48 8b 47 10 48 8b 40 48 c3 90 66 0f 1f 44 00 00 41 57 41 56 41 55 41 54 41 89 f4 55 48 89 fd 53 48 83 ec 18 4c 8b 7f 10 <49> 8b 87 c8 00 00 00 8b 48 0c 8b 58 08 89 4c 24 0c 89 5c 24 08 39" \ | sed 's/[<>]//g' | sed 's/ /, 0x/g' find /b ..., ..., 0x00, 0x00, 0x48, 0x8b, 0x47, 0x10, 0x48, 0x8b, 0x40, 0x48, 0xc3, 0x90, 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00, 0x41, 0x57, 0x41, 0x56, 0x41, 0x55, 0x41, 0x54, 0x41, 0x89, 0xf4, 0x55, 0x48, 0x89, 0xfd, 0x53, 0x48, 0x83, 0xec, 0x18, 0x4c, 0x8b, 0x7f, 0x10, 0x49, 0x8b, 0x87, 0xc8, 0x00, 0x00, 0x00, 0x8b, 0x48, 0x0c, 0x8b, 0x58, 0x08, 0x89, 0x4c, 0x24, 0x0c, 0x89, 0x5c, 0x24, 0x08, 0x39 # dpkg -S libKWaylandServer.so.5.20.5 libkwaylandserver5:amd64: /usr/lib/x86_64-linux-gnu/libKWaylandServer.so.5.20.5 $ gdb -q --pid $(pidof kwin_wayland) ... (gdb) set width 0 (gdb) set pagination off (gdb) info share From To Syms Read Shared Object Library 0x00007f6e16b80ff0 0x00007f6e16c32a66 Yes /lib/x86_64-linux-gnu/libKWaylandServer.so.5 ... (gdb) find /b 0x00007f6e16b80ff0, 0x00007f6e16c32a66, 0x00, 0x00, 0x48, 0x8b, 0x47, 0x10, 0x48, 0x8b, 0x40, 0x48, 0xc3, 0x90, 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00, 0x41, 0x57, 0x41, 0x56, 0x41, 0x55, 0x41, 0x54, 0x41, 0x89, 0xf4, 0x55, 0x48, 0x89, 0xfd, 0x53, 0x48, 0x83, 0xec, 0x18, 0x4c, 0x8b, 0x7f, 0x10, 0x49, 0x8b, 0x87, 0xc8, 0x00, 0x00, 0x00, 0x8b, 0x48, 0x0c, 0x8b, 0x58, 0x08, 0x89, 0x4c, 0x24, 0x0c, 0x89, 0x5c, 0x24, 0x08, 0x39 0x7f6e16bd523e 1 pattern found. (gdb) b * (0x7f6e16bd523e + 42) Breakpoint 1 at 0x7f6e16bd5268: file /usr/include/x86_64-linux-gnu/qt5/QtCore/qlist.h, line 116. (gdb) info b Num Type Disp Enb Address What 1 breakpoint keep y 0x00007f6e16bd5268 in QListData::isEmpty() const at /usr/include/x86_64-linux-gnu/qt5/QtCore/qlist.h:116 (gdb) disassemble /r 0x7f6e16bd523e, 0x7f6e16bd523e + 62 Dump of assembler code from 0x7f6e16bd523e to 0x7f6e16bd527c: 0x00007f6e16bd523e: 00 00 add %al,(%rax) 0x00007f6e16bd5240 <_ZNK14KWaylandServer16SurfaceInterface10compositorEv+0>: 48 8b 47 10 mov 0x10(%rdi),%rax 0x00007f6e16bd5244 <_ZNK14KWaylandServer16SurfaceInterface10compositorEv+4>: 48 8b 40 48 mov 0x48(%rax),%rax 0x00007f6e16bd5248 <_ZNK14KWaylandServer16SurfaceInterface10compositorEv+8>: c3 ret 0x00007f6e16bd5249: 90 nop 0x00007f6e16bd524a: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) 0x00007f6e16bd5250 <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+0>: 41 57 push %r15 0x00007f6e16bd5252 <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+2>: 41 56 push %r14 0x00007f6e16bd5254 <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+4>: 41 55 push %r13 0x00007f6e16bd5256 <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+6>: 41 54 push %r12 0x00007f6e16bd5258 <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+8>: 41 89 f4 mov %esi,%r12d 0x00007f6e16bd525b <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+11>: 55 push %rbp 0x00007f6e16bd525c <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+12>: 48 89 fd mov %rdi,%rbp 0x00007f6e16bd525f <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+15>: 53 push %rbx 0x00007f6e16bd5260 <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+16>: 48 83 ec 18 sub $0x18,%rsp 0x00007f6e16bd5264 <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+20>: 4c 8b 7f 10 mov 0x10(%rdi),%r15 -> 0x00007f6e16bd5268 <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+24>: 49 8b 87 c8 00 00 00 mov 0xc8(%r15),%rax 0x00007f6e16bd526f <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+31>: 8b 48 0c mov 0xc(%rax),%ecx 0x00007f6e16bd5272 <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+34>: 8b 58 08 mov 0x8(%rax),%ebx 0x00007f6e16bd5275 <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+37>: 89 4c 24 0c mov %ecx,0xc(%rsp) 0x00007f6e16bd5279 <_ZN14KWaylandServer16SurfaceInterface13frameRenderedEj+41>: 89 5c 24 08 mov %ebx,0x8(%rsp) End of assembler dump. set width 0 set pagination off info share find /b 0x00007f6e16b80ff0, 0x00007f6e16c32a66, 0x00, 0x00, 0x48, 0x8b, 0x47, 0x10, 0x48, 0x8b, 0x40, 0x48, 0xc3, 0x90, 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00, 0x41, 0x57, 0x41, 0x56, 0x41, 0x55, 0x41, 0x54, 0x41, 0x89, 0xf4, 0x55, 0x48, 0x89, 0xfd, 0x53, 0x48, 0x83, 0xec, 0x18, 0x4c, 0x8b, 0x7f, 0x10, 0x49, 0x8b, 0x87, 0xc8, 0x00, 0x00, 0x00, 0x8b, 0x48, 0x0c, 0x8b, 0x58, 0x08, 0x89, 0x4c, 0x24, 0x0c, 0x89, 0x5c, 0x24, 0x08, 0x39 b * (0x7f6e16bd523e + 42) info b disassemble /r 0x7f6e16bd523e, 0x7f6e16bd523e + 62 https://demangler.com/ -- _ZN14KWaylandServer16SurfaceInterface13frameRenderedEj -> KWaylandServer::SurfaceInterface::frameRendered(unsigned int) https://sources.debian.org/src/kwayland-server/5.20.5-1/src/server/surface_interface.cpp/#L417 https://bugs.kde.org/show_bug.cgi?id=428399