drm/amdgpu: drop the dma-buf reference when a KFD import fails

import_obj_create() takes a reference on the dma-buf for the new kgd_mem,
but the error path after validating the BO doesn't drop it. Since the
validation reserves the BO interruptibly, an import failing with
-ERESTARTSYS leaks the exported BO with its memory, and keeps the module
in use.

Importing a 64 MiB VRAM BO in a loop while getting SIGUSR1
every 20 us and another thread changes the BO's mappings:

  INFO: 171821 imports, VRAM used before 65 MiB, after 129 MiB
  modprobe: FATAL: Module amdgpu is in use.

Drop the reference, and free the sync object and the mutex of the kgd_mem
as well. With that VRAM usage returns to 65 MiB after the same test.

Fixes: 0e2e7c5b3d71 ("drm/amdgpu: Attach eviction fence on alloc")
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit b4d1eca2729840148ff2ea957724ce764ca5a94e)
Cc: stable@vger.kernel.org

0 files changed, 0 insertions, 0 deletions