[asterisk-dev] [Code Review] Make ast_unload_resource actually remove the module from the module list when it is unloaded

Mark Michelson reviewboard at asterisk.org
Mon Feb 20 14:33:40 CST 2012


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I think a better idea is to call both ast_unload_resource() and ast_module_unregister() in res_calendar.c.

- Mark


On Feb. 18, 2012, 1:31 p.m., Terry Wilson wrote:
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> (Updated Feb. 18, 2012, 1:31 p.m.)
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> 
> Review request for Asterisk Developers.
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> Summary
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> res_calendar calls ast_unload_resource for the related tech modules when it is unloaded. If this happens through a 'core stop gracefully', then it will be unloading the tech modules that are already in the list that is being traversed (supposedly safely) for unloading, eventually causing a double free. The problem seems to be that ast_unload_resource, while it calls the unload() callback function for the module, does not actually unlink the module from the list of modules. So the AST_LIST_TRAVERSE_SAFE_BEGIN {} still iterates over the unloaded module.
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> This patch causes ast_unload_resource to call AST_LIST_REMOVE on successfully unloaded modules.
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> Diffs
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>   /trunk/main/loader.c 355783 
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> Diff: https://reviewboard.asterisk.org/r/1752/diff
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> Testing
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> Scenario: Start Asterisk with res_calendar and assorted calendar tech modules loaded. Run 'core stop gracefully'.
> Before patch: Crash.
> After patch: No crash.
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> 
> Thanks,
> 
> Terry
> 
>

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