[PATCH] drm/amdgpu: Check hive->reset_domain not NULL before releasing it.

[Gavin Wan]

The recent change brought a bug on SRIOV envrionment. It caused
kernel crashing while unloading amdgpu on guest VM with hive
configuration. The reason is that the hive->reset_domain is not
used (hive->reset_domain is not initialized) for SRIOV, but the
code did not check if hive->reset_domain before releasing.

The hive->reset_domain need be checked not NULL before releasing.

Fixed: d95e8e97e2d5 ("drm/amdgpu: refine create and release logic of hive info")
Signed-off-by: Gavin Wan <Gavin.Wan at amd.com>
Change-Id: I17189e4d7357e399c6b70e43c24051356c025a3a
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
index 47159e9a0884..371c4f1aac2b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
@@ -217,8 +217,15 @@ static void amdgpu_xgmi_hive_release(struct kobject *kobj)
 	struct amdgpu_hive_info *hive = container_of(
 		kobj, struct amdgpu_hive_info, kobj);
 
-	amdgpu_reset_put_reset_domain(hive->reset_domain);
-	hive->reset_domain = NULL;
+	/**
+	 * The hive->reset_domain is only initialized for none SRIOV
+	 * configuration. It needs to check if hive->reset_domain is
+	 * NULL.
+	 */
+	if (hive->reset_domain) {
+		amdgpu_reset_put_reset_domain(hive->reset_domain);
+		hive->reset_domain = NULL;
+	}
 
 	mutex_destroy(&hive->hive_lock);
 	kfree(hive);
-- 
2.34.1