https://bugs.kde.org/show_bug.cgi?id=510116
Jeff Stokes <[email protected]> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |[email protected] --- Comment #3 from Jeff Stokes <[email protected]> --- Here's the report, ready to paste: --- **Title:** kwin_wayland segfault in `KWin::ConfinedPointerV1Interface::region()` on alt-tab out of fullscreen game using pointer confinement **Product:** kwin **Component:** input **Version:** 6.7.3 **Severity:** crash **Platform:** Arch Linux (CachyOS) **Summary:** kwin_wayland segfaults and restarts when alt-tabbing out of a fullscreen game that uses pointer confinement (`zwp_pointer_constraints_v1`). The compositor crash takes down all Wayland clients (game, Steam, browser) with it. Crash is a null-pointer read (SIGSEGV, error 4) inside `ConfinedPointerV1Interface::region()`, reached via `KWin::Transaction::apply()` during Wayland event dispatch — appears to be a use-after-free / stale-pointer access as the pointer confinement is torn down on focus-out. **Steps to reproduce:** 1. Launch a borderless-full screen game game that confines the cursor for mouselook (Wayland-native or XWayland). 2. Alt-tab out of the game to another window. 3. Sometimes kwin_wayland segfaults and auto-restarts; all graphical clients die. (chrome/discord/steam on my machine) **Reproducibility:** intermittent **Backtrace** (partial symbols — CachyOS build, debug info not available via debuginfod): ``` #0 KWin::ConfinedPointerV1Interface::region() const () from /usr/lib/libkwin.so.6 #1 ?? () from /usr/lib/libkwin.so.6 #3 ?? () from /usr/lib/libkwin.so.6 #4 ?? () from /usr/lib/libkwin.so.6 #5 KWin::Transaction::apply() () from /usr/lib/libkwin.so.6 #8 ffi_call () from /usr/lib/libffi.so.8 #11 wl_event_loop_dispatch () from /usr/lib/libwayland-server.so.0 #12 KWin::Display::dispatchEvents() () from /usr/lib/libkwin.so.6 #14 QSocketNotifier::event(QEvent*) #21 QCoreApplication::exec() ``` dmesg: `segfault at 10 ... error 4 in libkwin.so.6.7.3` (read fault at offset 0x10 off a near-null pointer). **Environment:** - KWin/Plasma 6.7.3 - Qt 6 (Wayland session) - Mesa 26.1.5, RADV - AMD Radeon RX 9070 XT (RDNA4) - Kernel: CachyOS (sched_ext/scx_lavd active) -- You are receiving this mail because: You are watching all bug changes.
