Android Native Code MemoryLeak Detection

In this post we will discuss how memory leaks in native code can be detected in Android.

The libmemunreachable provided by Google can be used to detect memory leak of a running process [1].

The below command will helps us to know whether leak is occuring or not [1]. If leak occurs it displays number of Bytes of leak and other memory related information of the process [1].

$ adb shell dumpsys -t 10000000000 meminfo --unreachable [process]

If libmemunreachable used along with Malloc Debug can help us get the backtrace of leak which can help us to figure/root cause the leak location in native library [1] [2].

The following commands helps us to do so [1].

$ adb root
# Command enables malloc debug for all zygote (app_process is a process which starts other process in Android) started process.
$ adb shell setprop libc.debug.malloc.program app_process
# To enable malloc_debug backtraces on allocations for a single app process
$ adb shell setprop wrap.[process] "\$\@"
# Set libc malloc options
$ adb shell setprop libc.debug.malloc.options backtrace=4
# Will Get memory leak information along with backtrace
$ adb shell dumpsys -t 10000000000 meminfo --unreachable [process]

The backtrace can be integer value of 8 or 16.

Commands to disable above are

$ adb shell setprop libc.debug.malloc.options "''"
$ adb shell setprop libc.debug.malloc.program "''"
$ adb shell setprop wrap.[process]  "''"

References:

[1] libmemunreachable
[2] Malloc Debug