drm/amdkfd: don't drop an SVM CWSR reference that was never taken

When kfd_queue_acquire_buffers() fails, its error path calls
kfd_queue_release_buffers(), which also drops a queue_refcount on the
SVM range at ctx_save_restore_area_address. The SVM range is the last
buffer acquired, and kfd_queue_buffer_svm_get() takes no reference when
it fails, so on every error path this reference was never taken. If
another queue of the process uses that CWSR range, its reference is
dropped instead, and unmapping the range no longer evicts that queue
while its CWSR area is unmapped from the GPU.

On navi31, with queue A using an SVM CWSR range: munmap() of the range
logs

  Freeing queue vital buffer 0x..., queue evicted

but after a CREATE_QUEUE that reuses A's CWSR address with an unmapped
write pointer (-EINVAL), the same munmap() leaves A running without the
message.

Only put the BOs on the acquire error path. The warning and the eviction
are back after the failed CREATE_QUEUE.

Fixes: b049504e211e ("drm/amdkfd: Validate user queue svm memory residency")
Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 9a08122e6361ef73f4b512d5db9596d561305519)
Cc: stable@vger.kernel.org

0 files changed, 0 insertions, 0 deletions