[asterisk-dev] [Code Review] 2567: Add backtrace generation to MALLOC_DEBUG

rmudgett reviewboard at asterisk.org
Fri May 31 20:04:14 CDT 2013


-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
https://reviewboard.asterisk.org/r/2567/#review8751
-----------------------------------------------------------

Ship it!


Other than mmichelson's concern this looks good to me.


/trunk/main/astmm.c
<https://reviewboard.asterisk.org/r/2567/#comment17169>

    You probably want to put the bt member after the node member to avoid any unnecessary padding.



/trunk/main/astmm.c
<https://reviewboard.asterisk.org/r/2567/#comment17170>

    Stray blank line.


- rmudgett


On May 27, 2013, 6:33 p.m., Matt Jordan wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://reviewboard.asterisk.org/r/2567/
> -----------------------------------------------------------
> 
> (Updated May 27, 2013, 6:33 p.m.)
> 
> 
> Review request for Asterisk Developers and rmudgett.
> 
> 
> Repository: Asterisk
> 
> 
> Description
> -------
> 
> Richard's patch that added a 'mini-valgrind' into Asterisk is incredibly useful. When you have a memory corruption, it will tell you the particular location in Asterisk that allocated the memory. Unfortunately, this often simply tells you the needle to look for in a stack of needles. For example, a memory corruption caused by improper JSON reference counting may just tell you this:
> 
> WARNING: Memory corrupted after free of 0x27eb8e0 allocated at json.c json_malloc() line 52
> 
> Since there's a whole mess of json_malloc calls, this is only so useful.
> 
> Luckily, we have backtrace generation in Asterisk - which is used primarily by DEBUG_THREADS and locations where Asterisk with DO_CRASH enabled will abort. This patch refactors the backtrace generation code into its own translation unit so that astmm.c can get at it safely, and adds an ast_bt object to the region memory structure. When a memory region is allocated or used, a backtrace is generated so that if the memory becomes corrupted, we know who originally allocated it.
> 
> That turns the previous line into this:
> 
> WARNING: Memory corrupted after free of 0x27eb8e0 allocated at json.c json_malloc() line 52
> Memory allocation backtrace:
> #0: [0x4593e5] main/astmm.c:498 __ast_malloc() (0x4593a9+3C)
> #1: [0x532f3a] main/json.c:53 json_malloc()
> #2: [0x7f9e93c3a8ca] src/value.c:40 json_object() (0x7f9e93c3a8b0+1A)
> #3: [0x7f9e93c396dd] src/pack_unpack.c:91 pack_object()
> #4: [0x7f9e93c39be0] src/pack_unpack.c:550 json_vpack_ex() (0x7f9e93c39b50+90)
> #5: [0x533ce6] main/json.c:496 ast_json_vpack() (0x533caa+3C)
> #6: [0x533c9a] main/json.c:488 ast_json_pack() (0x533bfb+9F)
> #7: [0x44e580] main/asterisk.c:1168 publish_fully_booted()
> #8: [0x4583bd] main/asterisk.c:4444 main()
> 
> 
> Diffs
> -----
> 
>   /trunk/include/asterisk/backtrace.h PRE-CREATION 
>   /trunk/include/asterisk/lock.h 389768 
>   /trunk/include/asterisk/logger.h 389768 
>   /trunk/main/astmm.c 389768 
>   /trunk/main/astobj2.c 389768 
>   /trunk/main/backtrace.c PRE-CREATION 
>   /trunk/main/logger.c 389768 
>   /trunk/utils/extconf.c 389768 
> 
> Diff: https://reviewboard.asterisk.org/r/2567/diff/
> 
> 
> Testing
> -------
> 
> Fixed two memory corruptions thanks to this patch. Yay MALLOC_DEBUG.
> 
> 
> Thanks,
> 
> Matt Jordan
> 
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.digium.com/pipermail/asterisk-dev/attachments/20130601/11a79c8d/attachment-0001.htm>


More information about the asterisk-dev mailing list