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This is an automatically generated e-mail. To reply, visit:
<a href="https://reviewboard.asterisk.org/r/2567/">https://reviewboard.asterisk.org/r/2567/</a>
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<a href="https://reviewboard.asterisk.org/r/2567/diff/2/?file=38955#file38955line176" style="color: black; font-weight: bold; text-decoration: underline;">/trunk/main/backtrace.c</a>
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(Diff revision 2)
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="k">if</span> <span class="p">(</span><span class="n">syms</span><span class="p">)</span> <span class="p">{</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="n">free</span><span class="p">(</span><span class="n">syms</span><span class="p">);</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="tb"> </span><span class="p">}</span></pre></td>
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<pre style="margin-left: 2em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">You don't need the if here. Freeing NULL is kosher.</pre>
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<p>- Tilghman</p>
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<p>On June 2nd, 2013, 1:39 a.m. UTC, Matt Jordan wrote:</p>
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<div>Review request for Asterisk Developers and rmudgett.</div>
<div>By Matt Jordan.</div>
<p style="color: grey;"><i>Updated June 2, 2013, 1:39 a.m.</i></p>
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<b style="color: #575012; font-size: 10pt;">Repository: </b>
Asterisk
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">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()
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Fixed two memory corruptions thanks to this patch. Yay MALLOC_DEBUG.</pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<li>/trunk/include/asterisk/backtrace.h <span style="color: grey">(PRE-CREATION)</span></li>
<li>/trunk/include/asterisk/lock.h <span style="color: grey">(390349)</span></li>
<li>/trunk/include/asterisk/logger.h <span style="color: grey">(390349)</span></li>
<li>/trunk/main/astmm.c <span style="color: grey">(390349)</span></li>
<li>/trunk/main/astobj2.c <span style="color: grey">(390349)</span></li>
<li>/trunk/main/backtrace.c <span style="color: grey">(PRE-CREATION)</span></li>
<li>/trunk/main/logger.c <span style="color: grey">(390349)</span></li>
<li>/trunk/utils/extconf.c <span style="color: grey">(390349)</span></li>
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<p><a href="https://reviewboard.asterisk.org/r/2567/diff/" style="margin-left: 3em;">View Diff</a></p>
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