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From:   Tong Zhang <ztong0001@gmail.com>
To:     Alex Deucher <alexander.deucher@amd.com>,
        =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>, amd-gfx@lists.freedesktop.org,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Cc:     Tong Zhang <ztong0001@gmail.com>
Subject: [PATCH v2] drm/radeon: don't evict if not initialized
Date:   Sun, 21 Mar 2021 11:19:07 -0400
Message-Id: <20210321151907.367586-1-ztong0001@gmail.com>
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TTM_PL_VRAM may not initialized at all when calling
radeon_bo_evict_vram(). We need to check before doing eviction.

[    2.160837] BUG: kernel NULL pointer dereference, address: 0000000000000020
[    2.161212] #PF: supervisor read access in kernel mode
[    2.161490] #PF: error_code(0x0000) - not-present page
[    2.161767] PGD 0 P4D 0
[    2.163088] RIP: 0010:ttm_resource_manager_evict_all+0x70/0x1c0 [ttm]
[    2.168506] Call Trace:
[    2.168641]  radeon_bo_evict_vram+0x1c/0x20 [radeon]
[    2.168936]  radeon_device_fini+0x28/0xf9 [radeon]
[    2.169224]  radeon_driver_unload_kms+0x44/0xa0 [radeon]
[    2.169534]  radeon_driver_load_kms+0x174/0x210 [radeon]
[    2.169843]  drm_dev_register+0xd9/0x1c0 [drm]
[    2.170104]  radeon_pci_probe+0x117/0x1a0 [radeon]

Suggested-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
---
v2: coding style fix

 drivers/gpu/drm/radeon/radeon_object.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index 9b81786782de..499ce55e34cc 100644
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -384,6 +384,8 @@ int radeon_bo_evict_vram(struct radeon_device *rdev)
 	}
 #endif
 	man = ttm_manager_type(bdev, TTM_PL_VRAM);
+	if (!man)
+		return 0;
 	return ttm_resource_manager_evict_all(bdev, man);
 }
 
-- 
2.25.1