kernel/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c, branch linux-6.1.y

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

2025-12-06T21:12:31Z

[ 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: Handle null atom context in VBIOS info ioctl

2023-10-06T12:56:54Z

[ Upstream commit 5e7e82254270c8cf8b107451c5de01cee2f135ae ] On some APU systems, there is no atom context and so the atom_context struct is null. Add a check to the VBIOS_INFO branch of amdgpu_info_ioctl to handle this case, returning all zeroes. Reviewed-by: Alex Deucher Signed-off-by: David Francis Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amdgpu: Update min() to min_t() in 'amdgpu_info_ioctl'

2023-09-13T07:42:41Z

[ Upstream commit a0cc8e1512ad72c9f97cdcb76d42715730adaf62 ] Fixes the following: WARNING: min() should probably be min_t(size_t, size, sizeof(ip)) + ret = copy_to_user(out, &ip, min((size_t)size, sizeof(ip))); And other style fixes: WARNING: Prefer 'unsigned int' to bare use of 'unsigned' WARNING: Missing a blank line after declarations Cc: Christian König Cc: Alex Deucher Signed-off-by: Srinivasan Shanmugam Reviewed-by: Alex Deucher Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amdgpu: correct MES debugfs versions

2022-11-02T20:57:32Z

Use mes.sched_version, mes.kiq_version for debugfs as mes.ucode_fw_version does not contain correct versioning information. Signed-off-by: Graham Sider Reviewed-by: Jack Xiao Signed-off-by: Alex Deucher

drm/amd: Add IMU fw version to fw version queries

2022-10-24T18:44:03Z

IMU is a new firmware for GFX11. There are four means by which firmware version can be queried from the driver: device attributes, vf2pf, debugfs, and the AMDGPU_INFO_FW_VERSION option in the amdgpu info ioctl. Add IMU as an option for those four methods. V2: Added debugfs Reviewed-by: Likun Gao Reviewed-by: Alex Deucher Signed-off-by: David Francis Signed-off-by: Alex Deucher

drm/amdgpu: add MES and MES-KIQ version in debugfs

2022-09-19T19:10:04Z

This patch addes MES and MES-KIQ version in debugfs. Signed-off-by: Yifan Zhang Reviewed-by: Tim Huang Acked-by: Alex Deucher Signed-off-by: Alex Deucher

drm/amdgpu: add rlcv/rlcp version info to debugfs

2022-09-19T19:07:40Z

amdgpu_firmware_info debugfs will show rlcv/rlcp ucode version info Signed-off-by: Hawking Zhang Reviewed-by: Likun Gao Reviewed-by: Feifei Xu Signed-off-by: Alex Deucher

Merge drm/drm-next into drm-misc-next

2022-08-01T14:04:00Z

Backmerging to pick up fixes from amdgpu. Signed-off-by: Thomas Zimmermann

drm/amdgpu: use idr_init_base() to initialize fpriv->bo_list_handles

2022-07-28T14:35:55Z

idr_init_base(), implemented by commit 6ce711f27500 ("idr: Make 1-based IDRs more efficient"), let us set an arbitrary base other than idr_init(), which uses base 0. Since, for this IDR, no ID < 1 is ever requested/allocated, using idr_init_base(&idr, 1) avoids unnecessary tree walks. Signed-off-by: Danilo Krummrich Signed-off-by: Maxime Ripard Link: https://lore.kernel.org/r/20220701185303.284082-3-dakr@redhat.com

drm/amdgpu: add the IP discovery IP versions for HW INFO data

2022-07-25T13:31:03Z

Use the former pad element to store the IP versions from the IP discovery table. This allows userspace to get the IP version from the kernel to better align with hardware IP versions. Proposed mesa patch: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17411/diffs?commit_id=c8a63590dfd0d64e6e6a634dcfed993f135dd075 Reviewed-by: Marek Olšák Signed-off-by: Alex Deucher