Properly mark kfd_process->ef as __rcu and consistently access it with
rcu_dereference_protected.

Reported-by: kernel test robot <l...@intel.com>
Closes: 
https://lore.kernel.org/oe-kbuild-all/202312052245.yfpbsgnh-...@intel.com/
Signed-off-by: Felix Kuehling <felix.kuehl...@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h       | 2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 4 ++--
 drivers/gpu/drm/amd/amdkfd/kfd_priv.h            | 2 +-
 drivers/gpu/drm/amd/amdkfd/kfd_process.c         | 6 ++++--
 4 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
index f2e920734c98..20cb266dcedd 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
@@ -314,7 +314,7 @@ void amdgpu_amdkfd_gpuvm_unmap_gtt_bo_from_kernel(struct 
kgd_mem *mem);
 int amdgpu_amdkfd_map_gtt_bo_to_gart(struct amdgpu_device *adev, struct 
amdgpu_bo *bo);
 
 int amdgpu_amdkfd_gpuvm_restore_process_bos(void *process_info,
-                                           struct dma_fence **ef);
+                                           struct dma_fence __rcu **ef);
 int amdgpu_amdkfd_gpuvm_get_vm_fault_info(struct amdgpu_device *adev,
                                              struct kfd_vm_fault_info *info);
 int amdgpu_amdkfd_gpuvm_import_dmabuf_fd(struct amdgpu_device *adev, int fd,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index 7d91f99acb59..8ba6f6c8363d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -2806,7 +2806,7 @@ static void amdgpu_amdkfd_restore_userptr_worker(struct 
work_struct *work)
        put_task_struct(usertask);
 }
 
-static void replace_eviction_fence(struct dma_fence **ef,
+static void replace_eviction_fence(struct dma_fence __rcu **ef,
                                   struct dma_fence *new_ef)
 {
        struct dma_fence *old_ef = rcu_replace_pointer(*ef, new_ef, true
@@ -2841,7 +2841,7 @@ static void replace_eviction_fence(struct dma_fence **ef,
  * 7.  Add fence to all PD and PT BOs.
  * 8.  Unreserve all BOs
  */
-int amdgpu_amdkfd_gpuvm_restore_process_bos(void *info, struct dma_fence **ef)
+int amdgpu_amdkfd_gpuvm_restore_process_bos(void *info, struct dma_fence __rcu 
**ef)
 {
        struct amdkfd_process_info *process_info = info;
        struct amdgpu_vm *peer_vm;
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h 
b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index 45366b4ca976..5a24097a9f28 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -917,7 +917,7 @@ struct kfd_process {
         * fence will be triggered during eviction and new one will be created
         * during restore
         */
-       struct dma_fence *ef;
+       struct dma_fence __rcu *ef;
 
        /* Work items for evicting and restoring BOs */
        struct delayed_work eviction_work;
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index 71df51fcc1b0..14b11d61f8dd 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -1110,6 +1110,8 @@ static void kfd_process_wq_release(struct work_struct 
*work)
 {
        struct kfd_process *p = container_of(work, struct kfd_process,
                                             release_work);
+       struct dma_fence *ef = rcu_dereference_protected(p->ef,
+               kref_read(&p->ref) == 0);
 
        kfd_process_dequeue_from_all_devices(p);
        pqm_uninit(&p->pqm);
@@ -1118,7 +1120,7 @@ static void kfd_process_wq_release(struct work_struct 
*work)
         * destroyed. This allows any BOs to be freed without
         * triggering pointless evictions or waiting for fences.
         */
-       dma_fence_signal(p->ef);
+       dma_fence_signal(ef);
 
        kfd_process_remove_sysfs(p);
 
@@ -1127,7 +1129,7 @@ static void kfd_process_wq_release(struct work_struct 
*work)
        svm_range_list_fini(p);
 
        kfd_process_destroy_pdds(p);
-       dma_fence_put(p->ef);
+       dma_fence_put(ef);
 
        kfd_event_free_process(p);
 
-- 
2.34.1

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