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Zack Rusin authored
v3: Fix vmw_user_bo_lookup which was also dropping the gem reference before the kernel was done with buffer depending on userspace doing the right thing. Same bug, different spot. It is possible for userspace to predict the next buffer handle and to destroy the buffer while it's still used by the kernel. Delay dropping the internal reference on the buffers until kernel is done with them. Instead of immediately dropping the gem reference in vmw_user_bo_lookup and vmw_gem_object_create_with_handle let the callers decide when they're ready give the control back to userspace. Also fixes the second usage of vmw_gem_object_create_with_handle in vmwgfx_surface.c which wasn't grabbing an explicit reference to the gem object which could have been destroyed by the userspace on the owning surface at any point. Signed-off-by:
Zack Rusin <zackr@vmware.com> Fixes: 8afa13a0 ("drm/vmwgfx: Implement DRIVER_GEM") Reviewed-by:
Martin Krastev <krastevm@vmware.com> Reviewed-by:
Maaz Mombasawala <mombasawalam@vmware.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230211050514.2431155-1-zack@kde.org (cherry picked from commit 9ef8d83e) Cc: <stable@vger.kernel.org> # v5.17+
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