[PATCH] drm/radeon: don't evict if not initialized

[Tong Zhang <ztong0001@gmail.com>]

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]

Signed-off-by: Tong Zhang <ztong0001@gmail.com>
---
 drivers/gpu/drm/radeon/radeon_object.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index 9b81786782de..04e9a8118b0e 100644
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -384,7 +384,9 @@ int radeon_bo_evict_vram(struct radeon_device *rdev)
 	}
 #endif
 	man = ttm_manager_type(bdev, TTM_PL_VRAM);
-	return ttm_resource_manager_evict_all(bdev, man);
+	if (man)
+		return ttm_resource_manager_evict_all(bdev, man);
+	return 0;
 }
 
 void radeon_bo_force_delete(struct radeon_device *rdev)
-- 
2.25.1