[PATCH] drm/amdgpu: fix IP instance memory leak on kobject add failure

[Guangshuo Li]

amdgpu_discovery_sysfs_ips() allocates ip_hw_instance with
kzalloc_flex() and initializes its embedded kobject before calling
kobject_add().

If kobject_add() fails, the return value is ignored and execution
continues without dropping the initial kobject reference. The failed
kobject is not retained in the kset list, so the normal sysfs teardown
path cannot find it. As a result, ip_hw_instance_release() is never
called and the ip_hw_instance allocation is leaked.

Call kobject_put() when kobject_add() fails so the initial reference is
dropped and ip_hw_instance_release() can free the allocation. Keep the
existing best-effort sysfs behavior by continuing with the remaining IP
entries after the failed registration.

The issue was identified by a static analysis tool I developed and
confirmed by manual review.

Fixes: a6c40b178092 ("drm/amdgpu: Show IP discovery in sysfs")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
index a404d8aa13ee..4b1ad1c0a10b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
@@ -1314,6 +1314,8 @@ static int amdgpu_discovery_sysfs_ips(struct amdgpu_device *adev,
 			ip_hw_instance->kobj.kset = &ip_hw_id->hw_id_kset;
 			res = kobject_add(&ip_hw_instance->kobj, NULL,
 					  "%d", ip_hw_instance->num_instance);
+			if (res)
+				kobject_put(&ip_hw_instance->kobj);
 next_ip:
 			if (reg_base_64)
 				ip_offset += struct_size(ip, base_address_64,
-- 
2.43.0