[PATCH] drm/amdgpu: Fix runtime PM leak in amdgpu_debugfs_test_ib_show()

[Wentao Liang]

amdgpu_debugfs_test_ib_show() resumes the device with
pm_runtime_get_sync() before taking the reset domain semaphore with
down_write_killable().  If the write lock acquisition is interrupted,
the function returns without calling pm_runtime_put_autosuspend(),
leaking the runtime PM reference acquired for the device and keeping
the GPU awake.

Drop the runtime PM reference on the interrupted down_write_killable()
error path before returning.

Fixes: 6049db43d6dd ("drm/amdgpu: change reset lock from mutex to rw_semaphore")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Wentao Liang <vulab@xxxxxxxxxxx>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
index 092fd3309099..adc0252f6400 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
@@ -1764,8 +1764,10 @@ static int amdgpu_debugfs_test_ib_show(struct seq_file *m, void *unused)
 
 	/* Avoid accidently unparking the sched thread during GPU reset */
 	r = down_write_killable(&adev->reset_domain->sem);
-	if (r)
+	if (r) {
+		pm_runtime_put_autosuspend(dev->dev);
 		return r;
+	}
 
 	/* hold on the scheduler */
 	for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
-- 
2.34.1