[RFC PATCH 1/1] drm/amdgpu: Fix null-ptr-deref in amdgpu_device_fini_sw()

[Zhang Boyang]

After amdgpu_device_init() failed, adev->reset_domain may be NULL. Thus
subsequent call to amdgpu_device_fini_sw() may result in null-ptr-deref.

This patch fixes the problem by adding a NULL pointer check around the
code of releasing adev->reset_domain in amdgpu_device_fini_sw().

Fixes: cfbb6b004744 ("drm/amdgpu: Rework reset domain to be refcounted.")

Signed-off-by: Zhang Boyang <zhangboyang...@gmail.com>
Link: 
https://lore.kernel.org/lkml/a8bce489-8ccc-aa95-3de6-f854e03ad...@suddenlinkmail.com/
Link: https://lore.kernel.org/lkml/at9whr.3z1t3vi9a2...@att.net/
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index be7aff2d4a57..204daad06b32 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -4021,8 +4021,10 @@ void amdgpu_device_fini_sw(struct amdgpu_device *adev)
        if (adev->mman.discovery_bin)
                amdgpu_discovery_fini(adev);
 
-       amdgpu_reset_put_reset_domain(adev->reset_domain);
-       adev->reset_domain = NULL;
+       if (adev->reset_domain) {
+               amdgpu_reset_put_reset_domain(adev->reset_domain);
+               adev->reset_domain = NULL;
+       }
 
        kfree(adev->pci_state);
 
-- 
2.30.2