As shown through runtime testing, the "filename" allocation is not always freed in perf_event_parse_addr_filter(). There are three possible ways that this could happen: - It could be allocated twice on subsequent iterations through the loop, - or leaked on the success path, - or on the failure path. Clean up the code flow to make it obvious that 'filename' is always freed in the reallocation path and in the two return paths as well. We rely on the fact that kfree(NULL) is NOP and filename is initialized with NULL. This fixes the leak. No other side effects expected. [ Dan Carpenter: cleaned up the code flow & added a changelog. ] [ Ingo Molnar: updated the changelog some more. ]
Unified · Split
| @@ -10085,6 +10085,7 @@ perf_event_parse_addr_filter(struct perf_event *event, char *fstr, · 10084 unmodified lines | |||
| 10085 | if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) { | 10085 | if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) { |
| 10086 | int fpos = token == IF_SRC_FILE ? 2 : 1; | 10086 | int fpos = token == IF_SRC_FILE ? 2 : 1; |
| 10087 | 10087 | ||
| 10088 | kfree(filename); | ||
| 10088 | filename = match_strdup(&args[fpos]); | 10089 | filename = match_strdup(&args[fpos]); |
| 10089 | if (!filename) { | 10090 | if (!filename) { |
| 10090 | ret = -ENOMEM; | 10091 | ret = -ENOMEM; |
| @@ -10131,16 +10132,13 @@ perf_event_parse_addr_filter(struct perf_event *event, char *fstr, · 40 unmodified lines | |||
| 10131 | */ | 10132 | */ |
| 10132 | ret = -EOPNOTSUPP; | 10133 | ret = -EOPNOTSUPP; |
| 10133 | if (!event->ctx->task) | 10134 | if (!event->ctx->task) |
| 10134 | goto fail_free_name; | 10135 | goto fail; |
| 10135 | 10136 | ||
| 10136 | /* look up the path and grab its inode */ | 10137 | /* look up the path and grab its inode */ |
| 10137 | ret = kern_path(filename, LOOKUP_FOLLOW, | 10138 | ret = kern_path(filename, LOOKUP_FOLLOW, |
| 10138 | &filter->path); | 10139 | &filter->path); |
| 10139 | if (ret) | 10140 | if (ret) |
| 10140 | goto fail_free_name; | 10141 | goto fail; |
| 10141 | |||
| 10142 | kfree(filename); | ||
| 10143 | filename = NULL; | ||
| 10144 | 10142 | ||
| 10145 | ret = -EINVAL; | 10143 | ret = -EINVAL; |
| 10146 | if (!filter->path.dentry || | 10144 | if (!filter->path.dentry || |
| @@ -10160,13 +10158,13 @@ perf_event_parse_addr_filter(struct perf_event *event, char *fstr, · 13 unmodified lines | |||
| 10160 | if (state != IF_STATE_ACTION) | 10158 | if (state != IF_STATE_ACTION) |
| 10161 | goto fail; | 10159 | goto fail; |
| 10162 | 10160 | ||
| 10161 | kfree(filename); | ||
| 10163 | kfree(orig); | 10162 | kfree(orig); |
| 10164 | 10163 | ||
| 10165 | return 0; | 10164 | return 0; |
| 10166 | 10165 | ||
| 10167 | fail_free_name: | ||
| 10168 | kfree(filename); | ||
| 10169 | fail: | 10166 | fail: |
| 10167 | kfree(filename); | ||
| 10170 | free_filters_list(filters); | 10168 | free_filters_list(filters); |
| 10171 | kfree(orig); | 10169 | kfree(orig); |
| 10172 | 10170 | ||