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

[wdoekes]

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Looks/behaves sane to me, but I'll defer the ship-it to someone else.


/trunk/res/res_calendar.c
<https://reviewboard.asterisk.org/r/1752/#comment10250>

    If it's now not possible to unload res_calendar before unloading those that depend on it, shouldn't this be replaced with an assert(AST_LIST_EMPTY(&techs)) ?


- wdoekes


On Feb. 22, 2012, 12:12 p.m., Terry Wilson wrote:
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> (Updated Feb. 22, 2012, 12:12 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/include/asterisk/calendar.h 356213 
>   /trunk/main/loader.c 356213 
>   /trunk/res/res_calendar.c 356213 
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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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>

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