[PATCH 1/1] drm/amdgpu: Fix double release KFD pasid

[Philip Yang]

If amdgpu_amdkfd_gpuvm_acquire_process_vm returns failed after vm is
converted to KFD vm and vm->pasid set to KFD pasid, KFD will not
take pdd->drm_file reference, as a result, drm close file handler maybe
called to release the KFD pasid before KFD process destroy to release
the same pasid and set vm->pasid to zero, this generates below WARNING
backtrace and NULL pointer access.

For compute process, KFD manage pasid and drm close file handler should
not release KFD pasid to avoid double release.

 amdgpu: Failed to create process VM object

 ida_free called for id=32770 which is not allocated.
 WARNING: CPU: 57 PID: 72542 at ../lib/idr.c:522 ida_free+0x96/0x140
 RIP: 0010:ida_free+0x96/0x140
 Call Trace:
  amdgpu_pasid_free_delayed+0xe1/0x2a0 [amdgpu]
  amdgpu_driver_postclose_kms+0x2d8/0x340 [amdgpu]
  drm_file_free.part.13+0x216/0x270 [drm]
  drm_close_helper.isra.14+0x60/0x70 [drm]
  drm_release+0x6e/0xf0 [drm]
  __fput+0xcc/0x280
  ____fput+0xe/0x20
  task_work_run+0x96/0xc0
  do_exit+0x3d0/0xc10

 BUG: kernel NULL pointer dereference, address: 0000000000000000
 RIP: 0010:ida_free+0x76/0x140
 Call Trace:
  amdgpu_pasid_free_delayed+0xe1/0x2a0 [amdgpu]
  amdgpu_driver_postclose_kms+0x2d8/0x340 [amdgpu]
  drm_file_free.part.13+0x216/0x270 [drm]
  drm_close_helper.isra.14+0x60/0x70 [drm]
  drm_release+0x6e/0xf0 [drm]
  __fput+0xcc/0x280
  ____fput+0xe/0x20
  task_work_run+0x96/0xc0
  do_exit+0x3d0/0xc10

Suggested-by: Felix Kuehling <Felix.Kuehling at amd.com>
Signed-off-by: Philip Yang <Philip.Yang at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index efc0a13e9aea..bf444c3f6656 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -1244,8 +1244,14 @@ void amdgpu_driver_postclose_kms(struct drm_device *dev,
 		amdgpu_bo_unreserve(adev->virt.csa_obj);
 	}
 
-	pasid = fpriv->vm.pasid;
+	if (fpriv->vm.is_compute_context)
+		/* pasid managed by KFD is released when process is destroyed */
+		pasid = 0;
+	else
+		pasid = fpriv->vm.pasid;
+
 	pd = amdgpu_bo_ref(fpriv->vm.root.bo);
+
 	if (!WARN_ON(amdgpu_bo_reserve(pd, true))) {
 		amdgpu_vm_bo_del(adev, fpriv->prt_va);
 		amdgpu_bo_unreserve(pd);
-- 
2.35.1