android malloc_debug tool
130|console:/ # cat /data/local.prop libc.debug.malloc.options=backtrace=16 guard=8 fill_on_free=16 free_track=2046 leak_track libc.debug.malloc.program=slub_debug_test.bin
在/data/local.prop里写了上述内容后，一般需要重启下系统，重启后看下slub_debug_test.bin进程的maps里是否有链接libc_malloc_debug.so，如果有，说明正常。
上面options里加了leak_track，但是只有在slub_debug_test.bin退出后，才会将mem leak信息打印出来，这有些鸡肋..
打印出来的log在logcat，例如：
console:/ # logcat |grep malloc_debug 09-22 15:24:56.400 4914 4914 E malloc_debug: +++ slub_debug_test.bin leaked block of size 16384 at 0x7b690a17f0 (leak 1 of 2) 09-22 15:24:56.400 4914 4914 E malloc_debug: Backtrace at time of allocation: 09-22 15:24:56.402 4914 4914 E malloc_debug: #00 pc 00000000000011f0 /vendor/bin/slub_debug_test.bin 09-22 15:24:56.402 4914 4914 E malloc_debug: #01 pc 000000000007d844 /apex/com.android.runtime/lib64/bionic/libc.so (__libc_init+108) 09-22 15:24:56.402 4914 4914 E malloc_debug: #02 pc 0000000000000000 <unknown> 09-22 15:24:56.402 4914 4914 E malloc_debug: +++ slub_debug_test.bin leaked block of size 8 at 0x7b6900a5b0 (leak 2 of 2) 09-22 15:24:56.402 4914 4914 E malloc_debug: Backtrace at time of allocation: 09-22 15:24:56.404 4914 4914 E malloc_debug: #00 pc 00000000000d64e8 /apex/com.android.runtime/lib64/bionic/libc.so 09-22 15:24:56.404 4914 4914 E malloc_debug: #01 pc 000000000008b208 /apex/com.android.runtime/lib64/bionic/libc.so (newlocale+160) 09-22 15:24:56.404 4914 4914 E malloc_debug: #02 pc 000000000009956c /system/lib64/vndk-sp-29/libc++.so 09-22 15:24:56.404 4914 4914 E malloc_debug: #03 pc 000000000009f1b8 /system/lib64/vndk-sp-29/libc++.so (std::__1::locale::__global()+160) 09-22 15:24:56.404 4914 4914 E malloc_debug: #04 pc 000000000009f218 /system/lib64/vndk-sp-29/libc++.so (std::__1::locale::locale()+16) 09-22 15:24:56.404 4914 4914 E malloc_debug: #05 pc 0000000000075c5c /system/lib64/vndk-sp-29/libc++.so (std::__1::basic_streambuf<char, std::__1::char_traits<char>>::basic_streambuf()+36) 09-22 15:24:56.404 4914 4914 E malloc_debug: #06 pc 00000000000815d4 /system/lib64/vndk-sp-29/libc++.so (std::__1::ios_base::Init::Init()+68) 09-22 15:24:56.404 4914 4914 E malloc_debug: #07 pc 0000000000082890 /system/lib64/vndk-sp-29/libc++.so 09-22 15:24:56.404 4914 4914 E malloc_debug: #08 pc 0000000000050d08 /apex/com.android.runtime/bin/linker64 09-22 15:24:56.404 4914 4914 E malloc_debug: #09 pc 0000000000050f20 /apex/com.android.runtime/bin/linker64 09-22 15:24:56.404 4914 4914 E malloc_debug: #10 pc 0000000000050e2c /apex/com.android.runtime/bin/linker64 09-22 15:24:56.404 4914 4914 E malloc_debug: #11 pc 000000000004ce70 /apex/com.android.runtime/bin/linker64 09-22 15:24:56.404 4914 4914 E malloc_debug: #12 pc 000000000004c03c /apex/com.android.runtime/bin/linker64 09-22 15:24:56.404 4914 4914 E malloc_debug: #13 pc 00000000000533f4 /apex/com.android.runtime/bin/linker64 09-22 15:24:56.404 4914 4914 E malloc_debug: #14 pc 0000000000000000 <unknown>
slub_debug_test.bin main函数如下，malloc一个16KB后的buffer后就return了：
... unsigned char *ptr = (unsigned char *)malloc(16*1024); printf("the alloced mem: 0x%lx. ", (unsigned long)ptr); return 0; }
reference:
https://android.googlesource.com/platform/bionic/+/master/libc/malloc_debug/README.md