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

From: Zhang Boyang <zhangboyang.id@gmail.com>
To: "Andrey Grodzovsky" <andrey.grodzovsky@amd.com>,
	"Christian König" <christian.koenig@amd.com>,
	linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org
Cc: "David C . Rankin" <drankinatty@suddenlinkmail.com>,
	Steven J Abner <pheonix.sja@att.net>,
	Zhang Boyang <zhangboyang.id@gmail.com>
Subject: [RFC PATCH 1/1] drm/amdgpu: Fix null-ptr-deref in amdgpu_device_fini_sw()
Date: Sat,  1 Oct 2022 05:41:10 +0800	[thread overview]
Message-ID: <20220930214110.1074226-2-zhangboyang.id@gmail.com> (raw)
In-Reply-To: <20220930214110.1074226-1-zhangboyang.id@gmail.com>

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.id@gmail.com>
Link: https://lore.kernel.org/lkml/a8bce489-8ccc-aa95-3de6-f854e03ad557@suddenlinkmail.com/
Link: https://lore.kernel.org/lkml/AT9WHR.3Z1T3VI9A2AQ3@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

