This is a note to let you know that I've just added the patch titled drm/amdgpu: Call find_vma under mmap_sem to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-amdgpu-call-find_vma-under-mmap_sem.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit be3184cd93d5afbdd9c44f5eef2abd0b896cb61e Author: Jason Gunthorpe <jgg@xxxxxxxxxxxx> Date: Tue Nov 12 16:22:27 2019 -0400 drm/amdgpu: Call find_vma under mmap_sem [ Upstream commit a9ae8731e6e52829a935d81a65d7f925cb95dbac ] find_vma() must be called under the mmap_sem, reorganize this code to do the vma check after entering the lock. Further, fix the unlocked use of struct task_struct's mm, instead use the mm from hmm_mirror which has an active mm_grab. Also the mm_grab must be converted to a mm_get before acquiring mmap_sem or calling find_vma(). Fixes: 66c45500bfdc ("drm/amdgpu: use new HMM APIs and helpers") Fixes: 0919195f2b0d ("drm/amdgpu: Enable amdgpu_ttm_tt_get_user_pages in worker threads") Link: https://lore.kernel.org/r/20191112202231.3856-11-jgg@xxxxxxxx Acked-by: Christian König <christian.koenig@xxxxxxx> Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx> Reviewed-by: Philip Yang <Philip.Yang@xxxxxxx> Tested-by: Philip Yang <Philip.Yang@xxxxxxx> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c index dff41d0a85fe..c0e41f1f0c23 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c @@ -35,6 +35,7 @@ #include <linux/hmm.h> #include <linux/pagemap.h> #include <linux/sched/task.h> +#include <linux/sched/mm.h> #include <linux/seq_file.h> #include <linux/slab.h> #include <linux/swap.h> @@ -788,7 +789,7 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages) struct hmm_mirror *mirror = bo->mn ? &bo->mn->mirror : NULL; struct ttm_tt *ttm = bo->tbo.ttm; struct amdgpu_ttm_tt *gtt = (void *)ttm; - struct mm_struct *mm = gtt->usertask->mm; + struct mm_struct *mm; unsigned long start = gtt->userptr; struct vm_area_struct *vma; struct hmm_range *range; @@ -796,25 +797,14 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages) uint64_t *pfns; int r = 0; - if (!mm) /* Happens during process shutdown */ - return -ESRCH; - if (unlikely(!mirror)) { DRM_DEBUG_DRIVER("Failed to get hmm_mirror\n"); - r = -EFAULT; - goto out; + return -EFAULT; } - vma = find_vma(mm, start); - if (unlikely(!vma || start < vma->vm_start)) { - r = -EFAULT; - goto out; - } - if (unlikely((gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) && - vma->vm_file)) { - r = -EPERM; - goto out; - } + mm = mirror->hmm->mmu_notifier.mm; + if (!mmget_not_zero(mm)) /* Happens during process shutdown */ + return -ESRCH; range = kzalloc(sizeof(*range), GFP_KERNEL); if (unlikely(!range)) { @@ -847,6 +837,17 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages) hmm_range_wait_until_valid(range, HMM_RANGE_DEFAULT_TIMEOUT); down_read(&mm->mmap_sem); + vma = find_vma(mm, start); + if (unlikely(!vma || start < vma->vm_start)) { + r = -EFAULT; + goto out_unlock; + } + if (unlikely((gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) && + vma->vm_file)) { + r = -EPERM; + goto out_unlock; + } + r = hmm_range_fault(range, 0); up_read(&mm->mmap_sem); @@ -865,15 +866,19 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages) } gtt->range = range; + mmput(mm); return 0; +out_unlock: + up_read(&mm->mmap_sem); out_free_pfns: hmm_range_unregister(range); kvfree(pfns); out_free_ranges: kfree(range); out: + mmput(mm); return r; }