[Bug]: KWin crashed again :smiley:

[zeroxoneafour]

Before you make the issue, confirm that

• You are running the master build from GitHub actions
• You have read the FAQ and the usage instructions
• You have searched pull requests and issues and have found none similar to your issue
• This problem comes from a failure in the tiling system and not a missing feature

Describe the bug

KWin crashes on half if you have one window in master, 2 in stack, and remove the one in master

To reproduce

Exactly what I said

Expected behavior

No crash

Relevant log output

Mar 30 16:14:35 vaughan-tufdash systemd-coredump[11095]: [🡕] Process 9968 (kwin_wayland) of user 1000 dumped core.
                                                         
                                                         Stack trace of thread 9968:
                                                         #0  0x0000703cf329d0b4 _ZNK4KWin16SurfaceInterface4sizeEv (libkwin.so.6 + 0x49d0b4)
                                                         #1  0x0000703cf31a1b6b n/a (libkwin.so.6 + 0x3a1b6b)
                                                         #2  0x0000703cf31443db n/a (libkwin.so.6 + 0x3443db)
                                                         #3  0x0000703cf311c2f5 _ZN4KWin4Tile9addWindowEPNS_6WindowE (libkwin.so.6 + 0x31c2f5)
                                                         #4  0x0000703cf3153eba _ZN4KWin6Window7setTileEPNS_4TileE (libkwin.so.6 + 0x353eba)
                                                         #5  0x0000703cf3118a2b _ZN4KWin4TileD2Ev (libkwin.so.6 + 0x318a2b)
                                                         #6  0x0000703cf3118b0c n/a (libkwin.so.6 + 0x318b0c)
                                                         #7  0x0000703cf077c6fb _ZN14QObjectPrivate14deleteChildrenEv (libQt6Core.so.6 + 0x17c6fb)
                                                         #8  0x0000703cf0780f38 _ZN7QObjectD1Ev (libQt6Core.so.6 + 0x180f38)
                                                         #9  0x0000703cf3118b0c n/a (libkwin.so.6 + 0x318b0c)
                                                         #10 0x0000703cf077c0d8 _ZN7QObject5eventEP6QEvent (libQt6Core.so.6 + 0x17c0d8)
                                                         #11 0x0000703cf18f438b _ZN19QApplicationPrivate13notify_helperEP7QObjectP6QEvent (libQt6Widgets.so.6 + 0xf438b)
                                                         #12 0x0000703cf0739818 _ZN16QCoreApplication15notifyInternal2EP7QObjectP6QEvent (libQt6Core.so.6 + 0x139818)
                                                         #13 0x0000703cf0739b9b _ZN23QCoreApplicationPrivate16sendPostedEventsEP7QObjectiP11QThreadData (libQt6Core.so.6 + 0x139b9b)
                                                         #14 0x0000703cf089f18f _ZN20QEventDispatcherUNIX13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt6Core.so.6 + 0x29f18f)
                                                         #15 0x0000703cf11b26e2 _ZN23QUnixEventDispatcherQPA13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt6Gui.so.6 + 0x5b26e2)
                                                         #16 0x0000703cf0743d6e _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt6Core.so.6 + 0x143d6e)
                                                         #17 0x0000703cf073c2b8 _ZN16QCoreApplication4execEv (libQt6Core.so.6 + 0x13c2b8)
                                                         #18 0x000059426b6f7dee n/a (kwin_wayland + 0x3cdee)
                                                         #19 0x0000703cf0043cd0 n/a (libc.so.6 + 0x25cd0)
                                                         #20 0x0000703cf0043d8a __libc_start_main (libc.so.6 + 0x25d8a)
                                                         #21 0x000059426b6fe425 n/a (kwin_wayland + 0x43425)
                                                         
                                                         Stack trace of thread 10014:
                                                         #0  0x0000703cf0126e66 epoll_wait (libc.so.6 + 0x108e66)
                                                         #1  0x0000703ce891acf9 n/a (libspa-support.so + 0x14cf9)
                                                         #2  0x0000703ce890c58d n/a (libspa-support.so + 0x658d)
                                                         #3  0x0000703ce8700e52 n/a (libpipewire-0.3.so.0 + 0x1be52)
                                                         #4  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #5  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 9996:
                                                         #0  0x0000703cf01190bf __poll (libc.so.6 + 0xfb0bf)
                                                         #1  0x0000703cef356306 n/a (libglib-2.0.so.0 + 0xb9306)
                                                         #2  0x0000703cef2f6712 g_main_context_iteration (libglib-2.0.so.0 + 0x59712)
                                                         #3  0x0000703cf09739c4 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt6Core.so.6 + 0x3739c4)
                                                         #4  0x0000703cf0743d6e _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt6Core.so.6 + 0x143d6e)
                                                         #5  0x0000703cf082106f _ZN7QThread4execEv (libQt6Core.so.6 + 0x22106f)
                                                         #6  0x0000703cf15dd9df n/a (libQt6DBus.so.6 + 0x299df)
                                                         #7  0x0000703cf08a0bd3 n/a (libQt6Core.so.6 + 0x2a0bd3)
                                                         #8  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #9  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10017:
                                                         #0  0x0000703cf00a5ebe n/a (libc.so.6 + 0x87ebe)
                                                         #1  0x0000703cf00a8750 pthread_cond_wait (libc.so.6 + 0x8a750)
                                                         #2  0x0000703ce1c8683c n/a (iris_dri.so + 0x8683c)
                                                         #3  0x0000703ce1c9e7ec n/a (iris_dri.so + 0x9e7ec)
                                                         #4  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #5  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10025:
                                                         #0  0x0000703cf00a5ebe n/a (libc.so.6 + 0x87ebe)
                                                         #1  0x0000703cf00a8a65 pthread_cond_timedwait (libc.so.6 + 0x8aa65)
                                                         #2  0x0000703cf08a3ba4 _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt6Core.so.6 + 0x2a3ba4)
                                                         #3  0x0000703cf08a64aa n/a (libQt6Core.so.6 + 0x2a64aa)
                                                         #4  0x0000703cf08a0bd3 n/a (libQt6Core.so.6 + 0x2a0bd3)
                                                         #5  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #6  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10020:
                                                         #0  0x0000703cf00a5ebe n/a (libc.so.6 + 0x87ebe)
                                                         #1  0x0000703cf00a8750 pthread_cond_wait (libc.so.6 + 0x8a750)
                                                         #2  0x0000703cf02d9e11 __gthread_cond_wait (libstdc++.so.6 + 0xd9e11)
                                                         #3  0x0000703cf31cfcf0 n/a (libkwin.so.6 + 0x3cfcf0)
                                                         #4  0x0000703cf31caffd n/a (libkwin.so.6 + 0x3caffd)
                                                         #5  0x0000703cf00ae6af n/a (libc.so.6 + 0x906af)
                                                         #6  0x0000703cf31cb3af n/a (libkwin.so.6 + 0x3cb3af)
                                                         #7  0x0000703cf0818555 n/a (libQt6Core.so.6 + 0x218555)
                                                         #8  0x0000703cf08a0bd3 n/a (libQt6Core.so.6 + 0x2a0bd3)
                                                         #9  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #10 0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10858:
                                                         #0  0x0000703cf00a5ebe n/a (libc.so.6 + 0x87ebe)
                                                         #1  0x0000703cf00a8a65 pthread_cond_timedwait (libc.so.6 + 0x8aa65)
                                                         #2  0x0000703cf08a3ba4 _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt6Core.so.6 + 0x2a3ba4)
                                                         #3  0x0000703cf08a64aa n/a (libQt6Core.so.6 + 0x2a64aa)
                                                         #4  0x0000703cf08a0bd3 n/a (libQt6Core.so.6 + 0x2a0bd3)
                                                         #5  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #6  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10859:
                                                         #0  0x0000703cf00a5ebe n/a (libc.so.6 + 0x87ebe)
                                                         #1  0x0000703cf00a8a65 pthread_cond_timedwait (libc.so.6 + 0x8aa65)
                                                         #2  0x0000703cf08a3ba4 _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt6Core.so.6 + 0x2a3ba4)
                                                         #3  0x0000703cf08a64aa n/a (libQt6Core.so.6 + 0x2a64aa)
                                                         #4  0x0000703cf08a0bd3 n/a (libQt6Core.so.6 + 0x2a0bd3)
                                                         #5  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #6  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10860:
                                                         #0  0x0000703cf00a5ebe n/a (libc.so.6 + 0x87ebe)
                                                         #1  0x0000703cf00a8a65 pthread_cond_timedwait (libc.so.6 + 0x8aa65)
                                                         #2  0x0000703cf08a3ba4 _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt6Core.so.6 + 0x2a3ba4)
                                                         #3  0x0000703cf08a64aa n/a (libQt6Core.so.6 + 0x2a64aa)
                                                         #4  0x0000703cf08a0bd3 n/a (libQt6Core.so.6 + 0x2a0bd3)
                                                         #5  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #6  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10001:
                                                         #0  0x0000703cf01190bf __poll (libc.so.6 + 0xfb0bf)
                                                         #1  0x0000703cef356306 n/a (libglib-2.0.so.0 + 0xb9306)
                                                         #2  0x0000703cef2f6712 g_main_context_iteration (libglib-2.0.so.0 + 0x59712)
                                                         #3  0x0000703cf09739c4 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt6Core.so.6 + 0x3739c4)
                                                         #4  0x0000703cf0743d6e _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt6Core.so.6 + 0x143d6e)
                                                         #5  0x0000703cf082116f _ZN7QThread3runEv (libQt6Core.so.6 + 0x22116f)
                                                         #6  0x0000703cf08a0bd3 n/a (libQt6Core.so.6 + 0x2a0bd3)
                                                         #7  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #8  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10021:
                                                         #0  0x0000703cf00a5ebe n/a (libc.so.6 + 0x87ebe)
                                                         #1  0x0000703cf00a8750 pthread_cond_wait (libc.so.6 + 0x8a750)
                                                         #2  0x0000703cf02d9e11 __gthread_cond_wait (libstdc++.so.6 + 0xd9e11)
                                                         #3  0x0000703cf31cfcf0 n/a (libkwin.so.6 + 0x3cfcf0)
                                                         #4  0x0000703cf31caffd n/a (libkwin.so.6 + 0x3caffd)
                                                         #5  0x0000703cf00ae6af n/a (libc.so.6 + 0x906af)
                                                         #6  0x0000703cf31cb3af n/a (libkwin.so.6 + 0x3cb3af)
                                                         #7  0x0000703cf0818555 n/a (libQt6Core.so.6 + 0x218555)
                                                         #8  0x0000703cf08a0bd3 n/a (libQt6Core.so.6 + 0x2a0bd3)
                                                         #9  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #10 0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 9999:
                                                         #0  0x0000703cf00a5ebe n/a (libc.so.6 + 0x87ebe)
                                                         #1  0x0000703cf00a8750 pthread_cond_wait (libc.so.6 + 0x8a750)
                                                         #2  0x0000703ce1c8683c n/a (iris_dri.so + 0x8683c)
                                                         #3  0x0000703ce1c9e7ec n/a (iris_dri.so + 0x9e7ec)
                                                         #4  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #5  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10000:
                                                         #0  0x0000703cf00a5ebe n/a (libc.so.6 + 0x87ebe)
                                                         #1  0x0000703cf00a8750 pthread_cond_wait (libc.so.6 + 0x8a750)
                                                         #2  0x0000703ce1c8683c n/a (iris_dri.so + 0x8683c)
                                                         #3  0x0000703ce1c9e7ec n/a (iris_dri.so + 0x9e7ec)
                                                         #4  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #5  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10016:
                                                         #0  0x0000703cf00a5ebe n/a (libc.so.6 + 0x87ebe)
                                                         #1  0x0000703cf00a8750 pthread_cond_wait (libc.so.6 + 0x8a750)
                                                         #2  0x0000703ce1c8683c n/a (iris_dri.so + 0x8683c)
                                                         #3  0x0000703ce1c9e7ec n/a (iris_dri.so + 0x9e7ec)
                                                         #4  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #5  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10018:
                                                         #0  0x0000703cf00a5ebe n/a (libc.so.6 + 0x87ebe)
                                                         #1  0x0000703cf00a8750 pthread_cond_wait (libc.so.6 + 0x8a750)
                                                         #2  0x0000703ce1c8683c n/a (iris_dri.so + 0x8683c)
                                                         #3  0x0000703ce1c9e7ec n/a (iris_dri.so + 0x9e7ec)
                                                         #4  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #5  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10015:
                                                         #0  0x0000703cf00a5ebe n/a (libc.so.6 + 0x87ebe)
                                                         #1  0x0000703cf00a8750 pthread_cond_wait (libc.so.6 + 0x8a750)
                                                         #2  0x0000703ce1c8683c n/a (iris_dri.so + 0x8683c)
                                                         #3  0x0000703ce1c9e7ec n/a (iris_dri.so + 0x9e7ec)
                                                         #4  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #5  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10857:
                                                         #0  0x0000703cf00a5ebe n/a (libc.so.6 + 0x87ebe)
                                                         #1  0x0000703cf00a8a65 pthread_cond_timedwait (libc.so.6 + 0x8aa65)
                                                         #2  0x0000703cf08a3ba4 _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt6Core.so.6 + 0x2a3ba4)
                                                         #3  0x0000703cf08a64aa n/a (libQt6Core.so.6 + 0x2a64aa)
                                                         #4  0x0000703cf08a0bd3 n/a (libQt6Core.so.6 + 0x2a0bd3)
                                                         #5  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #6  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10013:
                                                         #0  0x0000703cf01190bf __poll (libc.so.6 + 0xfb0bf)
                                                         #1  0x0000703cef356306 n/a (libglib-2.0.so.0 + 0xb9306)
                                                         #2  0x0000703cef2f6712 g_main_context_iteration (libglib-2.0.so.0 + 0x59712)
                                                         #3  0x0000703cf09739c4 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt6Core.so.6 + 0x3739c4)
                                                         #4  0x0000703cf0743d6e _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt6Core.so.6 + 0x143d6e)
                                                         #5  0x0000703cf082116f _ZN7QThread3runEv (libQt6Core.so.6 + 0x22116f)
                                                         #6  0x0000703cf08a0bd3 n/a (libQt6Core.so.6 + 0x2a0bd3)
                                                         #7  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #8  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10027:
                                                         #0  0x0000703cf01190bf __poll (libc.so.6 + 0xfb0bf)
                                                         #1  0x0000703cef356306 n/a (libglib-2.0.so.0 + 0xb9306)
                                                         #2  0x0000703cef2f6712 g_main_context_iteration (libglib-2.0.so.0 + 0x59712)
                                                         #3  0x0000703cf09739c4 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt6Core.so.6 + 0x3739c4)
                                                         #4  0x0000703cf0743d6e _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt6Core.so.6 + 0x143d6e)
                                                         #5  0x0000703cf082116f _ZN7QThread3runEv (libQt6Core.so.6 + 0x22116f)
                                                         #6  0x0000703cf08a0bd3 n/a (libQt6Core.so.6 + 0x2a0bd3)
                                                         #7  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #8  0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         
                                                         Stack trace of thread 10019:
                                                         #0  0x0000703cf01224ff ioctl (libc.so.6 + 0x1044ff)
                                                         #1  0x0000703cf04fb311 drmIoctl (libdrm.so.2 + 0x7311)
                                                         #2  0x0000703cf31ccc08 n/a (libkwin.so.6 + 0x3ccc08)
                                                         #3  0x0000703cf31cfb5f n/a (libkwin.so.6 + 0x3cfb5f)
                                                         #4  0x0000703cf31caffd n/a (libkwin.so.6 + 0x3caffd)
                                                         #5  0x0000703cf00ae6af n/a (libc.so.6 + 0x906af)
                                                         #6  0x0000703cf31cb3af n/a (libkwin.so.6 + 0x3cb3af)
                                                         #7  0x0000703cf0818555 n/a (libQt6Core.so.6 + 0x218555)
                                                         #8  0x0000703cf08a0bd3 n/a (libQt6Core.so.6 + 0x2a0bd3)
                                                         #9  0x0000703cf00a955a n/a (libc.so.6 + 0x8b55a)
                                                         #10 0x0000703cf0126a3c n/a (libc.so.6 + 0x108a3c)
                                                         ELF object binary architecture: AMD x86-64

Screenshots and videos

No response

Additional context

Awesome!

[djneba]

I can confirm.

[zeroxoneafour]

This bug is not present on KWin 6.0.2 but is on 6.0.3.1. I just downgraded to check, because I didn't remember writing anything to cause this.

[zeroxoneafour]

Yeah I'm not spending any more time debugging this personally. This needs to be fixed by KWin as well. So close to v1.0...

[zeroxoneafour]

Talked with KWin developers and issue has probably been found. I suggest staying on kwin 6.0.3 or lower until the patch is pushed out unless you really need to drag windows.

[zxq5-dev]

found another way to crash kwin

• set layout to monocle

• open around 7 windows
  (not sure the exact number but I haven't managed to crash it with less than 7)

• attempt to close one of the windows using the close window shortcut (eg. Alt+F4)

outcome:
another segfault

[zeroxoneafour]

@FantasyPvP can confirm that is the same crash. setTile method of some client causes the crash. The suspected reason for the crash is that the setTile method is called on the deleted client, which is why this bug only happens when closing windows.

[zxq5-dev]

@FantasyPvP can confirm that is the same crash. setTile method of some client causes the crash. The suspected reason for the crash is that the setTile method is called on the deleted client, which is why this bug only happens when closing windows.

that's weird, so far I've only had it crash when I've had 7-8 or so windows open at one time

[zeroxoneafour]

I believe the exact cause is a race condition between deleting clients and tiles.

[zeroxoneafour]

On kwin 6.0.3 exactly, dragging windows has been working for me (without #107 occurring or any failure to drag) as well as no crashes. It's very strange, as 6.0.2 failed to retile dragged windows and 6.0.3.1 has this bug.

If anyone else can downgrade to exactly 6.0.3 and can confirm this, that would probably be helpful to the KDE devs. Arch never had 6.0.3 in the official repos but I have a testing repo package downloaded that I can share. It works as a drop-in replacement to 6.0.3.1.

[CarlosEkisde]

I can confirm too.

[djneba]

I tried 6.0.3 and it's ok. I also tried 6.0.3.1-3 and it won't even let me log in. Crashes the entire session. All the versions between these two crash according to this bug.