drm/ttm: add a check against null pointer dereference

When calling ttm_range_man_fini(), 'man' may be uninitialized, which may
cause a null pointer dereference bug.

Fix this by checking if it is a null pointer.

This log reveals it:

[    7.902580 ] BUG: kernel NULL pointer dereference, address: 0000000000000058
[    7.905721 ] RIP: 0010:ttm_range_man_fini+0x40/0x160
[    7.911826 ] Call Trace:
[    7.911826 ]  radeon_ttm_fini+0x167/0x210
[    7.911826 ]  radeon_bo_fini+0x15/0x40
[    7.913767 ]  rs400_fini+0x55/0x80
[    7.914358 ]  radeon_device_fini+0x3c/0x140
[    7.914358 ]  radeon_driver_unload_kms+0x5c/0xe0
[    7.914358 ]  radeon_driver_load_kms+0x13a/0x200
[    7.914358 ]  ? radeon_driver_unload_kms+0xe0/0xe0
[    7.914358 ]  drm_dev_register+0x1db/0x290
[    7.914358 ]  radeon_pci_probe+0x16a/0x230
[    7.914358 ]  local_pci_probe+0x4a/0xb0

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1626274459-8148-1-git-send-email-zheyuma97@gmail.com
Signed-off-by: Christian König <christian.koenig@amd.com>

diff --git a/drivers/gpu/drm/ttm/ttm_range_manager.c b/drivers/gpu/drm/ttm/ttm_range_manager.c
index 03395386e8a7cbc8697f53230d26719ef2ca1e5a..f4b08a8705b320687fc8aa9d2db02e5b7a8013d9 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_range_manager.c
+++ b/drivers/gpu/drm/ttm/ttm_range_manager.c
@@ -181,6 +181,9 @@ int ttm_range_man_fini(struct ttm_device *bdev,
        struct drm_mm *mm = &rman->mm;
        int ret;
 
+       if (!man)
+               return 0;
+
        ttm_resource_manager_set_used(man, false);
 
        ret = ttm_resource_manager_evict_all(bdev, man);