使用mtrace追踪JVM堆外内存泄露的方法

$ pid=`pgrep java`
# 配置gdb不调试信号，避免JVM收到信号后被gdb暂停
$ cat <<"EOF" > ~/.gdbinit
handle all nostop noprint pass
handle SIGINT stop print nopass
EOF
# 设置MALLOC_TRACE环境变量，将内存分配操作记录在malloc_trace.log里
$ gdb -q -batch -ex 'call setenv("MALLOC_TRACE", "./malloc_trace.log", 1)' -p $pid
# 调用mtrace开启内存分配追踪
$ gdb -q -batch -ex 'call mtrace()' -p $pid
# 一段时间后，调用muntrace关闭追踪
$ gdb -q -batch -ex 'call muntrace()' -p $pid

$ mtrace malloc_trace.log | less -n
Memory not freed:
-----------------
           Address     Size     Caller
0x00007efe08008cc0     0x18  at 0x7efe726e8e5d
0x00007efe08008ea0    0x160  at 0x7efe726e8e5d
0x00007efe6cabca40     0x58  at 0x7efe715dc432
0x00007efe6caa9ad0   0x1bf8  at 0x7efe715e4b88
0x00007efe6caab6d0   0x1bf8  at 0x7efe715e4b88
0x00007efe6ca679c0   0x8000  at 0x7efe715e4947
# 按Caller分组统计一下，看看各Caller各泄露的次数及内存量
$ mtrace malloc_trace.log | sed '1,/Caller/d'|awk '{s[$NF]+=strtonum($2);n[$NF]++;}END{for(k in s){print k,n[k],s[k]}}'|column -t
0x7efe715e4b88  1010  7231600
0x7efe715dc432  1010  88880
0x7efe715e4947  997   32669696
0x7efe726e8e5d  532   309800
0x7efe715eb2f4  1     72
0x7efe715eb491  1     38

$ pmap -x $pid -p -A 0x7efe715e4b88
Address           Kbytes     RSS   Dirty Mode  Mapping
00007efe715d9000     108     108       0 r-x-- /opt/jdk8u222-b10/jre/lib/amd64/libzip.so
---------------- ------- ------- -------
total kB             108  163232  160716

# 指令地址减去动态库起始地址
$ printf "%x" $((0x7efe715e4b88-0x00007efe715d9000))
bb88

$ objdump -d /opt/jdk8u222-b10/jre/lib/amd64/libzip.so | less -n

gdb -q -batch -ex 'info symbol 0x7efe715e4b88' -p $pid

[arthas@1]$ profiler execute 'start,event=inflateInit2_,alluser'
Profiling started
[arthas@1]$ profiler stop
OK
profiler output file: .../arthas-output/20230923-173944.html

<dependency>
    <groupId>net.java.dev.jna</groupId>
    <artifactId>jna</artifactId>
    <version>4.2.2</version>
</dependency>

public class JnaTool {
    public interface CLibrary extends Library {
        void malloc_stats();
        void malloc_trim(int pad);
        void setenv(String name, String value, int overwrite);
        void mtrace();
        void muntrace();
    }
    private static CLibrary cLibrary;
    static {
        try {
            cLibrary = (CLibrary) Native.loadLibrary("c", CLibrary.class);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public static void mtrace(String traceFile) {
        if (cLibrary == null) return;
        cLibrary.setenv("MALLOC_TRACE", traceFile, 1);
        cLibrary.mtrace();
    }
    public static void muntrace() {
        if (cLibrary == null) return;
        cLibrary.muntrace();
    }
    public static void mallocStats() {
        if (cLibrary == null) return;
        cLibrary.malloc_stats();
    }
    public static void mallocTrim() {
        if (cLibrary == null) return;
        cLibrary.malloc_trim(0);
    }
}