зеркало из https://github.com/mozilla/pjs.git
91 строка
3.4 KiB
HTML
91 строка
3.4 KiB
HTML
|
<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
|
||
|
|
<html>
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
|
||
|
|
<meta name="GENERATOR" content="Mozilla/4.5 [en] (X11; I; Linux 2.0.36 i686) [Netscape]">
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
|
||
|
|
<h2>
|
||
|
|
About Leaky</h2>
|
||
|
|
Leaky is a program which will help you find memory leaks, and as of late,
|
||
|
|
help you debug reference count problems with xpcom objects.
|
||
|
|
<p>To use leaky you must first build it. I've made it work only on x86
|
||
|
|
linux. To work on other platforms you will need to:
|
||
|
|
<ol>
|
||
|
|
<li>
|
||
|
|
Implement CrawlStack in libmalloc.cpp</li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
Implement DumpAddressMap in libmalloc.cpp and in ShowLibs.cpp</li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
Either support LD_PRELOAD in your dynamic linker *or* produce a library
|
||
|
|
that wraps your libc malloc (see config.h for some clues)</li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
Implement symbol table reading code (see coff.cpp, elf.cpp and bfd.cpp
|
||
|
|
for examples; at the time of writing this document only bfd.cpp was known
|
||
|
|
to work)</li>
|
||
|
|
</ol>
|
||
|
|
After its built, you can use TestPreload and TestMalloc and ShowLibs to
|
||
|
|
debug your implementation.
|
||
|
|
<p>By setting the LIBMALLOC_LOG environment variable you control how much
|
||
|
|
information is logged during the programs execution. See libmalloc.h for
|
||
|
|
a definition of the values to use. If you are using LD_PRELOAD, here is
|
||
|
|
one way to run your program:
|
||
|
|
<blockquote><tt>env LD_PRELOAD=/full/path/to/libleaky.so LIBMALLOC_LOG=1
|
||
|
|
my-program</tt></blockquote>
|
||
|
|
The debugging malloc library creates two files - "malloc-log" and "malloc-map".
|
||
|
|
The malloc-log file can be quite large for large programs (e.g. mozilla)
|
||
|
|
so be prepared to have alot of disk space. The malloc-map is tiny.
|
||
|
|
<p>Once your program has completed execution you can use leaky to look
|
||
|
|
for memory leaks, or at least use it to dump the log. For memory leaks,
|
||
|
|
you use leaky like this:
|
||
|
|
<blockquote><tt>leaky -d <program-name-goes-here> malloc-log</tt></blockquote>
|
||
|
|
Leaky will then display all of the call sites where memory was leaked.
|
||
|
|
To look at the entire log file contents, not just the leaks add "-a" to
|
||
|
|
the arguments:
|
||
|
|
<blockquote><tt>leaky -d -a <program-name-goes-here> malloc-log</tt></blockquote>
|
||
|
|
For debugging reference count issues, here is what I do:
|
||
|
|
<ol>
|
||
|
|
<li>
|
||
|
|
Set LIBMALLOC_LOG to "8"</li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
Modify your source code so that your class::Addref and class::Release methods
|
||
|
|
call __log_addref and __log_release, as appropriate. See libmalloc.h for
|
||
|
|
their signatures.</li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
Run your program so that you get the log data. Its often convenient to
|
||
|
|
run your program in the debugger and then set a breakpoint at an interesting
|
||
|
|
location where you think some object is being leaked or over-freed. Then
|
||
|
|
when the debugger gets there tell it to execute DumpAddressMap. In gdb
|
||
|
|
you do this:</li>
|
||
|
|
|
||
|
|
<ol><tt></tt>
|
||
|
|
<br><tt>(gdb) p DumpAddressMap()</tt>
|
||
|
|
<br><tt></tt> </ol>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
Then use leaky to capture the addref and release calls to a log file:</li>
|
||
|
|
|
||
|
|
<ol>
|
||
|
|
<br><tt>leaky -d -a <program-name-goes-here> malloc-log > log</tt>
|
||
|
|
<br> </ol>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
Then use "grep" to search the log for a specific object by grepping for
|
||
|
|
its memory address...</li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
On a typical *short* run of mozilla, I'll end up with a malloc-log
|
||
|
|
file of around 5 to 10 megabytes and the resulting converted log file will
|
||
|
|
be 10 to 20 times that so be prepared to have alot of disk space. It helps
|
||
|
|
a great deal to narrow down your problem space to reduce the log file size...</li>
|
||
|
|
</ol>
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|