ws: do not export a stale buffer on a commit without attach - #206
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Surface::shmBuffer (and, in the EGL implementation, also dmabufBuffer) is set at wl_surface.attach and was never cleared: a commit without a fresh attach - e.g. one issued only for frame-callback pacing - re-exported the previous buffer pointer. Once the client had destroyed that buffer after its release, the embedder received a dangling wl_shm_buffer whose metadata reads as garbage (observed as negative width/stride crashing cog's drm renderer copy loop). Consume the attached buffer state at commit and export nothing when no buffer was attached. Apply to both ImplSHM and ImplEGL - the code is duplicated between ws-shm.cpp and ws-egl.cpp. Signed-off-by: Mirko Vogt <foss@mirko.in>
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Partially related to: Igalia/cog#794 |
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Surface::shmBuffer/dmabufBuffer were set at attach and never cleared; a commit without a fresh attach (frame-callback pacing) re-exported the previous - potentially dangling - buffer pointer, handing the embedder garbage buffer metadata. Consume the attached state at commit and export nothing without a buffer, in both ImplSHM and ImplEGL (upstream-ready patch with the full story). PKG_RELEASE 5. Patchset already proposed upstream: Igalia/WPEBackend-fdo#206 Assisted-By: Claude Opus + Fable Signed-off-by: Mirko Vogt <mirko-openwrt@nanl.de>
mirko
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Surface::shmBuffer/dmabufBuffer were set at attach and never cleared; a commit without a fresh attach (frame-callback pacing) re-exported the previous - potentially dangling - buffer pointer, handing the embedder garbage buffer metadata. Consume the attached state at commit and export nothing without a buffer, in both ImplSHM and ImplEGL (upstream-ready patch with the full story). PKG_RELEASE 5. Patchset already proposed upstream: Igalia/WPEBackend-fdo#206 Assisted-By: Claude Opus + Fable Signed-off-by: Mirko Vogt <mirko-openwrt@nanl.de>
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Surface::shmBuffer (and, in the EGL implementation, also dmabufBuffer) is set at wl_surface.attach and was never cleared: a commit without a fresh attach - e.g. one issued only for frame-callback pacing - re-exported the previous buffer pointer. Once the client had destroyed that buffer after its release, the embedder received a dangling wl_shm_buffer whose metadata reads as garbage (observed as negative width/stride crashing cog's drm renderer copy loop).
Consume the attached buffer state at commit and export nothing when no buffer was attached. Apply to both ImplSHM and ImplEGL - the code is duplicated between ws-shm.cpp and ws-egl.cpp.
Disclaimer: I used Claude by Anthropic to help with debugging and fixing this issue.