kremit / libleak

detect memory leak by LD_PRELOAD, without changing the target program

libleak

libleak detects memory leak by hooking memory functions (e.g. malloc) by LD_PRELOAD.

There is no need to modify or re-compile the target program, and you can enable/disable the detection during target running.

In fact libleak can not identify memory leak, while it just takes the memory as leak if it lives longer than a threshold. The threshold is 60 second by default, but you should set it according to your scenarios.

There is less impact on performance, compared with valgrind and memleax.

It prints the full call-stack at suspicious memory leak point, and easier to use, compared with other similar libraries (e.g. mtrace).

LICENCE

GPLv2

OS-MACHINE

• GNU/Linux only by now. But FreeBSD should be OK with some code changing

• x86_64 is only tested by now. But others should be OK.

BUILD FROM SOURCE

$ git clone --recursive https://github.com/WuBingzheng/libleak.git
$ cd libleak
$ make

USAGE

basic

1. Download or build the shared-object libleak.so.

2. Run the target program:

    $ LD_PRELOAD=/path/of/libleak.so ./a.out
   

3. Then you will read output in /tmp/libleak.$pid in time.

set expire threshold

As said above, you should set expire threshold according to your scenarios.

For example, if you are debugging an HTTP server with keepalive, and there are connections last for more than 5 minutes, you should set the threshold to 300 second to cover it. If your program is expected to free every memory in 1 second, you should set the threshold to 2 to get report in time.

The threshold is set by environment variable LEAK_EXPIRE (in second, default is 60):

$ LD_PRELOAD=/path/of/libleak.so LEAK_EXPIRE=300 ./a.out

Besides, the threshold will be increased if any memory block is freed after expiration, with LEAK_AUTO_EXPIRE enabled (default is disabled):

$ LD_PRELOAD=/path/of/libleak.so LEAK_AUTO_EXPIRE=1 ./a.out

enable/disable detection during running

libleak begins the detection at the very beginning of target process running by default. However you can enable/disable the detection during running by setting LEAK_PID_CHECK and LEAK_PID_FILE:

$ LD_PRELOAD=/path/of/libleak.so LEAK_PID_CHECK=10 ./a.out

LEAK_PID_CHECK set the interval (in second, default is 0) to check LEAK_PID_FILE.

LEAK_PID_FILE (default is /tmp/libleak.enabled) contains target pids: one pid each line, no empty line, no comment line. You can add or delete pids to/from this file during running.

To enable detecting process pid=1234:

$ echo 1234 >> /tmp/libleak.enabled

To disable detecting process pid=1234:

$ sed -i '/1234/d' /tmp/libleak.enabled

for multi-thread program

libleak is multi-thread safe.

for multi-process program

Log file will be created for each process.

Besides you can choose which processes to be detect by LEAK_PID_FILE and LEAK_PID_CHECK said above.

set the log

The log file is set by LEAK_LOG_FILE (default is /tmp/libleak.$pid).

There is also a statistics report when disabled or target normal termination, either via exit(3) or via return from the main().