Hello Tao Zhou,
The patch f9317014ea51: "drm/amdgpu: add function to creat all ras
debugfs node" from Mar 6, 2020, leads to the following static checker
warning:
drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c:1132 amdgpu_ras_debugfs_create_all()
warn: variable dereferenced before check 'obj' (see line 1131)
drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
1116 void amdgpu_ras_debugfs_create_all(struct amdgpu_device *adev)
1117 {
1118 struct amdgpu_ras *con = amdgpu_ras_get_context(adev);
1119 struct ras_manager *obj, *tmp;
1120 struct ras_fs_if fs_info;
1121
1122 /*
1123 * it won't be called in resume path, no need to check
1124 * suspend and gpu reset status
1125 */
1126 if (!con)
1127 return;
1128
1129 amdgpu_ras_debugfs_create_ctrl_node(adev);
1130
1131 list_for_each_entry_safe(obj, tmp, &con->head, node) {
1132 if (!obj)
^^^^
There is no need to check for NULL here, so just remove the check. The
other question is why is this using list_for_each_entry_safe() instead
of vanilla list_for_each_entry()? It doesn't seem to be freeing "obj"
or removing "obj" from the list which are basically the only reasons
why _safe() is used. Some people think _safe() has something to do with
locking but it doesn't.
Please remove the test and use vanilla list_for_each_entry().
1133 continue;
1134
1135 if (amdgpu_ras_is_supported(adev, obj->head.block) &&
1136 (obj->attr_inuse == 1)) {
1137 sprintf(fs_info.debugfs_name, "%s_err_inject",
1138 ras_block_str(obj->head.block));
1139 fs_info.head = obj->head;
1140 amdgpu_ras_debugfs_create(adev, &fs_info);
1141 }
1142 }
1143 }
regards,
dan carpenter
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