kernel.git/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c, branch linux-6.17.y

drm/amdgpu: Fix NULL pointer dereference in VRAM logic for APU devices

2025-11-24T09:37:25Z

[ Upstream commit 883f309add55060233bf11c1ea6947140372920f ] Previously, APU platforms (and other scenarios with uninitialized VRAM managers) triggered a NULL pointer dereference in `ttm_resource_manager_usage()`. The root cause is not that the `struct ttm_resource_manager *man` pointer itself is NULL, but that `man->bdev` (the backing device pointer within the manager) remains uninitialized (NULL) on APUs—since APUs lack dedicated VRAM and do not fully set up VRAM manager structures. When `ttm_resource_manager_usage()` attempts to acquire `man->bdev->lru_lock`, it dereferences the NULL `man->bdev`, leading to a kernel OOPS. 1. **amdgpu_cs.c**: Extend the existing bandwidth control check in `amdgpu_cs_get_threshold_for_moves()` to include a check for `ttm_resource_manager_used()`. If the manager is not used (uninitialized `bdev`), return 0 for migration thresholds immediately—skipping VRAM-specific logic that would trigger the NULL dereference. 2. **amdgpu_kms.c**: Update the `AMDGPU_INFO_VRAM_USAGE` ioctl and memory info reporting to use a conditional: if the manager is used, return the real VRAM usage; otherwise, return 0. This avoids accessing `man->bdev` when it is NULL. 3. **amdgpu_virt.c**: Modify the vf2pf (virtual function to physical function) data write path. Use `ttm_resource_manager_used()` to check validity: if the manager is usable, calculate `fb_usage` from VRAM usage; otherwise, set `fb_usage` to 0 (APUs have no discrete framebuffer to report). This approach is more robust than APU-specific checks because it: - Works for all scenarios where the VRAM manager is uninitialized (not just APUs), - Aligns with TTM's design by using its native helper function, - Preserves correct behavior for discrete GPUs (which have fully initialized `man->bdev` and pass the `ttm_resource_manager_used()` check). v4: use ttm_resource_manager_used(&adev->mman.vram_mgr.manager) instead of checking the adev->gmc.is_app_apu flag (Christian) Reviewed-by: Christian König Suggested-by: Lijo Lazar Signed-off-by: Jesse Zhang Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amdgpu: reject gang submissions under SRIOV

2025-11-13T20:37:24Z

[ Upstream commit d7ddcf921e7d0d8ebe82e89635bc9dc26ba9540d ] Gang submission means that the kernel driver guarantees that multiple submissions are executed on the HW at the same time on different engines. Background is that those submissions then depend on each other and each can't finish stand alone. SRIOV now uses world switch to preempt submissions on the engines to allow sharing the HW resources between multiple VFs. The problem is now that the SRIOV world switch can't know about such inter dependencies and will cause a timeout if it waits for a partially running gang submission. To conclude SRIOV and gang submissions are fundamentally incompatible at the moment. For now just disable them. Signed-off-by: Christian König Reviewed-by: Alex Deucher Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amdgpu: Use memdup_array_user in amdgpu_cs_wait_fences_ioctl

2025-11-13T20:37:22Z

[ Upstream commit dea75df7afe14d6217576dbc28cc3ec1d1f712fb ] Replace kmalloc_array() + copy_from_user() with memdup_array_user(). This shrinks the source code and improves separation between the kernel and userspace slabs. Signed-off-by: Tvrtko Ursulin Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amdgpu: fix task hang from failed job submission during process kill

2025-08-12T20:16:36Z

During process kill, drm_sched_entity_flush() will kill the vm entities. The following job submissions of this process will fail, and the resources of these jobs have not been released, nor have the fences been signalled, causing tasks to hang and timeout. Fix by check entity status in amdgpu_vm_ready() and avoid submit jobs to stopped entity. v2: add amdgpu_vm_ready() check before amdgpu_vm_clear_freed() in function amdgpu_cs_vm_handling(). Fixes: 1f02f2044bda ("drm/amdgpu: Avoid extra evict-restore process.") Signed-off-by: Liu01 Tong Signed-off-by: Lin.Cao Reviewed-by: Christian König Signed-off-by: Alex Deucher (cherry picked from commit f101c13a8720c73e67f8f9d511fbbeda95bcedb1)

Merge drm-next-2025-05-28 into drm-misc-next

2025-06-03T13:07:39Z

Christian needs a recent drm-next branch to merge fence patches. Signed-off-by: Maxime Ripard

drm/sched: Store the drm client_id in drm_sched_fence

2025-05-28T14:15:58Z

This will be used in a later commit to trace the drm client_id in some of the gpu_scheduler trace events. This requires changing all the users of drm_sched_job_init to add an extra parameter. The newly added drm_client_id field in the drm_sched_fence is a bit of a duplicate of the owner one. One suggestion I received was to merge those 2 fields - this can't be done right now as amdgpu uses some special values (AMDGPU_FENCE_OWNER_*) that can't really be translated into a client id. Christian is working on getting rid of those; when it's done we should be able to squash owner/drm_client_id together. Reviewed-by: Christian König Signed-off-by: Pierre-Eric Pelloux-Prayer Signed-off-by: Philipp Stanner Link: https://lore.kernel.org/r/20250526125505.2360-3-pierre-eric.pelloux-prayer@amd.com

drm/amdgpu: Add Support for enforcing isolation without Cleaner Shader

2025-05-05T17:29:53Z

Adjusted the enforce isolation setting handling to include the ability to disable the cleaner shader without affecting isolation between tasks. v2: Updated enforce isolation documentation and parameters. (Alex) Cc: Christian König Cc: Alex Deucher Signed-off-by: Srinivasan Shanmugam Reviewed-by: Alex Deucher Signed-off-by: Alex Deucher

drm/amdgpu: adjust enforce_isolation handling

2025-04-11T20:58:15Z

Switch from a bool to an enum and allow more options for enforce isolation. There are now 3 modes of operation: - Disabled (0) - Enabled (serialization and cleaner shader) (1) - Enabled in legacy mode (no serialization or cleaner shader) (2) This provides better flexibility for more use cases. Acked-by: Srinivasan Shanmugam Signed-off-by: Alex Deucher

drm/amdgpu: add ring flag for no user submissions

2025-04-08T20:48:22Z

This would be set by IPs which only accept submissions from the kernel, not userspace, such as when kernel queues are disabled. Don't expose the rings to userspace and reject any submissions in the CS IOCTL. v2: fix error code (Alex) Reviewed-by: Sunil Khatri Signed-off-by: Alex Deucher

drm/amdgpu: stop reserving VMIDs to enforce isolation

2025-03-21T16:16:34Z

That was quite troublesome for gang submit. Completely drop this approach and enforce the isolation separately. Signed-off-by: Christian König Acked-by: Srinivasan Shanmugam Signed-off-by: Alex Deucher