Arun please take a look at this. Thanks, Christian.
On 7/3/26 15:05, Thomas Hellström wrote: > drmm_cgroup_register_region() is called before INIT_LIST_HEAD() and > gpu_buddy_init() in amdgpu_vram_mgr_init(). If it fails, the function > returns early and bypasses those initializations. > > Since adev->mman.initialized is set to true before amdgpu_vram_mgr_init() > is called, a failure triggers amdgpu_ttm_fini(), which calls > amdgpu_vram_mgr_fini(), which then: > > - Calls list_for_each_entry_safe() on reservations_pending and > reserved_pages, whose list_head::next pointers are zero-initialized > (NULL). The loop does not recognize them as empty and dereferences NULL. > > - Calls gpu_buddy_fini(), which iterates free_trees[] unconditionally > via for_each_free_tree(). Since mm->free_trees is NULL > (never allocated), this dereferences NULL. > > Both result in a kernel panic on the module load error path. > > Fix by moving drmm_cgroup_register_region() to after the list and buddy > allocator are fully initialized, so the teardown path is safe to run. > > Reported-by: Sashiko-bot <[email protected]> > Closes: > https://sashiko.dev/#/patchset/[email protected]?part=4 > Fixes: 2b624a2c1865 ("drm/ttm: Handle cgroup based eviction in TTM") > Cc: Friedrich Vock <[email protected]> > Cc: Maarten Lankhorst <[email protected]> > Cc: Tejun Heo <[email protected]> > Cc: Maxime Ripard <[email protected]> > Cc: Christian König <[email protected]> > Cc: Alex Deucher <[email protected]> > Cc: [email protected] > Cc: [email protected] > Cc: <[email protected]> # v6.14+ > Assisted-by: GitHub_Copilot:claude-sonnet-4.6 > Signed-off-by: Thomas Hellström <[email protected]> > --- > drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c > b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c > index 2a241a5b12c4..ac3f71d77140 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c > @@ -918,9 +918,6 @@ int amdgpu_vram_mgr_init(struct amdgpu_device *adev) > struct ttm_resource_manager *man = &mgr->manager; > int err; > > - man->cg = drmm_cgroup_register_region(adev_to_drm(adev), "vram", > adev->gmc.real_vram_size); > - if (IS_ERR(man->cg)) > - return PTR_ERR(man->cg); > ttm_resource_manager_init(man, &adev->mman.bdev, > adev->gmc.real_vram_size); > > @@ -935,6 +932,10 @@ int amdgpu_vram_mgr_init(struct amdgpu_device *adev) > if (err) > return err; > > + man->cg = drmm_cgroup_register_region(adev_to_drm(adev), "vram", > adev->gmc.real_vram_size); > + if (IS_ERR(man->cg)) > + return PTR_ERR(man->cg); > + > ttm_set_driver_manager(&adev->mman.bdev, TTM_PL_VRAM, &mgr->manager); > ttm_resource_manager_set_used(man, true); > return 0;
