All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH v3 0/7] drm: Revert general use of struct drm_gem_object.dma_buf
@ 2025-07-15 15:58 Thomas Zimmermann
  2025-07-15 15:58 ` [PATCH v3 1/7] Revert "drm/virtio: Use dma_buf from GEM object instance" Thomas Zimmermann
                   ` (9 more replies)
  0 siblings, 10 replies; 11+ messages in thread
From: Thomas Zimmermann @ 2025-07-15 15:58 UTC (permalink / raw)
  To: simona, airlied, christian.koenig, torvalds, maarten.lankhorst,
	mripard, l.stach, linux+etnaviv, kraxel, christian.gmeiner,
	dmitry.osipenko, gurchetansingh, olvaffe, zack.rusin
  Cc: bcm-kernel-feedback-list, dri-devel, etnaviv, virtualization,
	intel-gfx, Thomas Zimmermann

Revert the use of drm_gem_object.dma_buf back to .import_attach->dmabuf
in the affected places. Separates references to imported and exported DMA
bufs within a GEM object; as before.

The dma_buf field in struct drm_gem_object is not stable over the object
instance's lifetime. The field becomes NULL when user space releases the
final GEM handle on the buffer object. This resulted in a NULL-pointer
deref.

Workarounds in commit 5307dce878d4 ("drm/gem: Acquire references on GEM
handles for framebuffers") and commit f6bfc9afc751 ("drm/framebuffer:
Acquire internal references on GEM handles") only solved the problem
partially. They especially don't work for buffer objects without a DRM
framebuffer associated.

v3:
- cc stable where necessary
v2:
- extended commit messages (Sima)
- drop the GEM-handle changes to be resolved separately

Thomas Zimmermann (7):
  Revert "drm/virtio: Use dma_buf from GEM object instance"
  Revert "drm/vmwgfx: Use dma_buf from GEM object instance"
  Revert "drm/etnaviv: Use dma_buf from GEM object instance"
  Revert "drm/prime: Use dma_buf from GEM object instance"
  Revert "drm/gem-framebuffer: Use dma_buf from GEM object instance"
  Revert "drm/gem-shmem: Use dma_buf from GEM object instance"
  Revert "drm/gem-dma: Use dma_buf from GEM object instance"

 drivers/gpu/drm/drm_gem_dma_helper.c         | 2 +-
 drivers/gpu/drm/drm_gem_framebuffer_helper.c | 8 ++++++--
 drivers/gpu/drm/drm_gem_shmem_helper.c       | 4 ++--
 drivers/gpu/drm/drm_prime.c                  | 8 +++++++-
 drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c  | 4 ++--
 drivers/gpu/drm/virtio/virtgpu_prime.c       | 5 +++--
 drivers/gpu/drm/vmwgfx/vmwgfx_gem.c          | 6 +++---
 7 files changed, 24 insertions(+), 13 deletions(-)

-- 
2.50.0


^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2025-07-16  7:40 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-07-15 15:58 [PATCH v3 0/7] drm: Revert general use of struct drm_gem_object.dma_buf Thomas Zimmermann
2025-07-15 15:58 ` [PATCH v3 1/7] Revert "drm/virtio: Use dma_buf from GEM object instance" Thomas Zimmermann
2025-07-15 15:58 ` [PATCH v3 2/7] Revert "drm/vmwgfx: " Thomas Zimmermann
2025-07-15 15:58 ` [PATCH v3 3/7] Revert "drm/etnaviv: " Thomas Zimmermann
2025-07-15 15:58 ` [PATCH v3 4/7] Revert "drm/prime: " Thomas Zimmermann
2025-07-15 15:58 ` [PATCH v3 5/7] Revert "drm/gem-framebuffer: " Thomas Zimmermann
2025-07-15 15:58 ` [PATCH v3 6/7] Revert "drm/gem-shmem: " Thomas Zimmermann
2025-07-15 15:58 ` [PATCH v3 7/7] Revert "drm/gem-dma: " Thomas Zimmermann
2025-07-15 18:15 ` [PATCH v3 0/7] drm: Revert general use of struct drm_gem_object.dma_buf Zack Rusin
2025-07-15 21:22 ` ✓ i915.CI.BAT: success for drm: Revert general use of struct drm_gem_object.dma_buf (rev3) Patchwork
2025-07-16  7:40 ` ✗ i915.CI.Full: failure " Patchwork

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.