Examples
Table of contents
Introcution
We discuss two examples here. In addition, we provide all the bug reports and doorway to the results and source code.
Bug Reports
The following table is the link to each bug report with PR if any. ✅ means CMind successfully localizes the bugs. ❌ means CMind fails to localize the bugs. The results and source code are in Link.
| # | Issue | PR / Commit | gpt-o4 | gpt-5 | Results |
|---|---|---|---|---|---|
| 1 | redis#14188 | redis#14191 | ✅ | ✅ | link |
| 2 | obs-studio#11888 | N/A | ✅ | ✅ | link |
| 3 | obs-studio#11457 | N/A | ✅ | ✅ | link |
| 4 | obs-studio#10512 | N/A | ✅ | ✅ | link |
| 5 | masscan#730 | masscan@66c5159 | ✅ | ✅ | link |
| 6 | masscan#391 | masscan#390 | ✅ | ✅ | link |
| 7 | zephyr#92388 | N/A | ❌ | ✅ | link |
| 8 | zephyr#92601 | zephyr#92996 | ✅ | ✅ | link |
| 9 | Sandboxie#4658 | N/A | ✅ | ✅ | link |
| 10 | Sandboxie#4267 | Sandboxie#4268 | ✅ | ✅ | link |
| 11 | libvips#4352 | libvips@8e7bdde | ❌ | ❌ | link |
| 12 | libvips#4170 | libvips#4474 | ❌ | ❌ | link |
| 13 | mgba#3452 | mgba@86453b8 | ✅ | ✅ | link |
| 14 | libvips#4104 | libvips#4105 | ✅ | ✅ | link |
| 15 | libvips#3984 | libvips#3990 | ❌ | ❌ | link |
| 16 | htop#1449 | htop#1450 | ✅ | ✅ | link |
| 17 | htop#1662 | N/A | ✅ | ✅ | link |
| 18 | redis#14184 | redis#14186 | ✅ | ✅ | link |
| 19 | htop#1650 | htop#1683 | ❌ | ❌ | link |
| 20 | mbedtls#8687 | mbedtls#8688 | ✅ | ✅ | link |
Examples
We discuss two examples in our Website. One is with stack trace in the bug report. One is without stack trace in the bug report. You can use the ID to retrieve the hypothesis as well.
Result4 with stack trace
Report ID: 7a3ed78200857e0
In this example, we included the stack trace in the bug reports. We found that CMind is able to refer to the similar functions for bug localization. More specifically, the issue is that mod in ApplicationAudioCaptureToolbar::Init becomes NULL when it is in the linux system and there no safety check on whether mod is NULL. However, We found that CMind can refer other similar functions such as DisplayCaptureToolbar to localize the bugs.
Here’s a concise summary of the bug chain based solely on the provided information:
1. The helper function
bool obs_module_get_locale_string(const obs_module_t *mod, …)
assumes its first argument (`mod`) is non-NULL and does
`mod->get_string(…)` without ever checking `mod` itself.
2. obs_module_get_locale_text calls obs_module_get_locale_string without adding any null-check around its `mod` parameter.
3. In all other toolbars (DisplayCaptureToolbar, AudioCaptureToolbar, WindowCaptureToolbar), after fetching a module via get_os_module they explicitly do
if (!mod) return;
thus avoiding any null dereference.
4. ApplicationAudioCaptureToolbar::Init, however, calls
obs_get_module("win-wasapi") → mod
then immediately calls
obs_module_get_locale_text(mod, …)
without checking whether `mod` is NULL.
5. On Linux, obs_get_module("win-wasapi") always returns NULL, so ApplicationAudioCaptureToolbar::Init ends up passing a NULL `mod` into obs_module_get_locale_text, which in turn passes it into obs_module_get_locale_string and dereferences mod->get_string, causing the crash.
Hypothesis
ApplicationAudioCaptureToolbar::Init fails to guard against a NULL module before requesting localized text, leading to a NULL-pointer dereference inside obs_module_get_locale_string. Specifically, we found that CMind cannot refer to similar functions for bug localization in this case.
Result4 without stack trace
Report ID: 755c0391819b8ce
In this example, we did not included the stack trace in the bug reports. We found that CMind only provided a high-level hypothesis.
Here’s what the three analyses agree on, distilled down to the two root bugs you can see in the provided reasoning:
1. Windows-only WASAPI toolbar callback is being registered on all platforms
– In obs_properties_dialog_register_toolbar (called as part of setting up a source’s Properties dialog), the WASAPI-specific toolbar-load callback obs_wasapi_source_toolbar_load is unconditionally hooked up—even on Linux, where it makes no sense.
– That means on Linux user actions end up pulling in an invalid or null function pointer.
2. Callback invocation isn’t protected against a null/invalid pointer
– When the toolbar-load event fires, obs_source_call_toolbar_callback (and/or obs_toolbar_load) fetches whatever callback pointer was registered and invokes it without checking for NULL or platform validity.
– The result on Linux is a straight null-pointer dereference in obs_wasapi_source_toolbar_load and a crash.