The memleak-finder from zncb

memleak-finder's Introduction

Memleak finder
Mathieu Desnoyers, May 2013

* memleak-finder.so

example usage:
LD_PRELOAD=<path_to>/memleak-finder.so appname

If you get e.g.:

[warning] trying to free unallocated ptr 0x18b2a70 caller 0x7fae7943dd57
or
[leak] ptr: 0x18b2350 size: 0x160 caller: 0x7fae7943e28f <symbol>

If you need to see local symbols as well ("static" function), you will
need to use gdb "disassemble 0x...". A trick to hook gdb on the program
after the leak printout is to add an assert(0) at the end of the library
destructor, and run the program after issuing ulimit -c unlimited to
gather a core dump of the application. Don't forget to compile your
program and libraries, and install the "-dbg" versions of the system
libraries if you want the make sure gdb can lookup their local symbols.

You can set the MEMLEAK_FINDER_PRINT environment variable to make the
shared object print every allocation/free on stderr.


* malloc-stats.so

LD_PRELOAD=<path_to>/malloc-stats.so appname

Then, kill with:

killall -SIGUSR2 appname

It will show the output of malloc_stats(3) on stderr of the application.

Example output:

Arena 0:
system bytes     =     135168
in use bytes     =      19360
Total (incl. mmap):
system bytes     =     135168
in use bytes     =      19360
max mmap regions =          0
max mmap bytes   =          0


* Credits

The design of this library is inspired by this presentation:

"Tips of malloc & free"
Tetsuyuki Kobayashi
2013.2.22 Embedded Linux Conference
http://events.linuxfoundation.org/images/stories/slides/elc2013_kobayashi_malloc.pdf

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