主页 / user-28092874

Xellos's questions

Martin Hope
Xellos
Asked: 2025-01-18 10:21:54 +0800 CST
  • 5

示例：Java 源代码Foo.java：

public class Foo {
    public static void main(String[] args) {}
};

我在 Ubuntu 24.04 docker 上运行它，并预装了地址清理器（包含泄漏清理器），另外还根据github 问题为 dlopen/dlclose 配备了一个拦截器。Java 编译器和启动器来自openjdk-8-jdk包。

javac Foo.java
LD_PRELOAD="/usr/lib/llvm-17/lib/clang/17/lib/linux/libclang_rt.asan-x86_64.so:/root/libinterceptor.so" java Foo

拦截器代码是

#define _GNU_SOURCE
#include <dlfcn.h>
#include <link.h>
#include <stdio.h>
#include <string.h>

int dlclose(void *handle) {
    printf("Intercepted a dlclose call, handle %ld\n", (intptr_t)handle);
    return 0;
}

void* dlopen(const char* filename, int flags){
    typedef void* (*dlopen_t)(const char*, int);
    dlopen_t original_dlopen = (dlopen_t)dlsym(RTLD_NEXT, "dlopen");

    flags |= RTLD_NODELETE;
    void *ret = original_dlopen(filename, flags);
    printf("Intercepted a dlopen call for %s, handle %ld, injecting RTLD_NODELETE\n", filename, (intptr_t)ret);
    return ret;
}

报告了许多（误报）内存泄漏。这很好，它们很可能是由于垃圾收集和泄漏清理程序无法理解那里发生了什么而造成的。我不是在问该如何处理它们，我知道我应该忽略它们，因为它们是误报，我只是用它们来演示手头的问题。lsan 错误输出的一部分：

Direct leak of 120 byte(s) in 1 object(s) allocated from:
    #0 0x7f3d1c0fb372 in malloc (/usr/lib/llvm-17/lib/clang/17/lib/linux/libclang_rt.asan-x86_64.so+0xfb372) (BuildId: 91f375f2a48c6b133a56d8cc059d017ae5de4982)
    #1 0x7f3d17f8c7b4  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x98c7b4) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #2 0x7f3d178d29bd  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x2d29bd) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #3 0x7f3d178d2a7a  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x2d2a7a) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #4 0x7f3d17af07a9  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x4f07a9) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #5 0x7f3d17a5ac4d  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x45ac4d) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #6 0x7f3d17a5c3ca  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x45c3ca) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #7 0x7f3d17a6323a  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x46323a) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #8 0x7f3d180c3a34  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0xac3a34) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #9 0x7f3d180c4680  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0xac4680) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #10 0x7f3d180c64c4  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0xac64c4) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #11 0x7f3d17af25d7  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x4f25d7) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #12 0x7f3d17af36b9  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x4f36b9) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #13 0x7f3d17e59707  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x859707) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #14 0x7f3d17e5b308  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x85b308) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #15 0x7f3d17ca99cb  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x6a99cb) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #16 0x7f3d07a24dc7  (<unknown module>)
    #17 0x7f3d07a080f5  (<unknown module>)
    #18 0x7f3d07a004e6  (<unknown module>)
    #19 0x7f3d17cb2884  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x6b2884) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #20 0x7f3d17d2e75e  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x72e75e) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #21 0x7f3d17d2efbf  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x72efbf) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #22 0x7f3d1bac6c8a in JNU_NewStringPlatform (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/libjava.so+0x1dc8a) (BuildId: 95ab745b31a25f66a623ffeaf6822cdc641c5fab)
    #23 0x7f3d1babf2cb in Java_java_lang_System_initProperties (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/libjava.so+0x162cb) (BuildId: 95ab745b31a25f66a623ffeaf6822cdc641c5fab)
    #24 0x7f3d07a185e6  (<unknown module>)
    #25 0x7f3d07a07e3f  (<unknown module>)
    #26 0x7f3d07a004e6  (<unknown module>)
    #27 0x7f3d17cb2884  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x6b2884) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #28 0x7f3d17cb115e  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x6b115e) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)
    #29 0x7f3d17cb179f  (/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so+0x6b179f) (BuildId: d38655f827ac6a65fdbe1898b1278717fdb89a4e)

问题在于：很多泄漏报告<unknown module>在堆栈跟踪中都有 s。我的问题是如何将它们转换为已知库，以便我可以跟踪发生的事情。我并不是专门询问 Java，这只是我遇到它的一个例子 - 但它可能特定于 Java 启动器或其他程序。

如果<unknown module>s 是由动态加载或卸载引起的，那么拦截dlopen或dlclose应该就足够了。但是，我得到的唯一标准输出是

Intercepted a dlopen call for /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server/libjvm.so, handle 89747636617344, injecting RTLD_NODELETE
Intercepted a dlopen call for librt.so.1, handle 89747636681856, injecting RTLD_NODELETE
Intercepted a dlopen call for /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/libverify.so, handle 89747636684928, injecting RTLD_NODELETE
Intercepted a dlopen call for /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/libjava.so, handle 89747636686464, injecting RTLD_NODELETE
Intercepted a dlopen call for /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/libzip.so, handle 89747636688000, injecting RTLD_NODELETE
Intercepted a dlopen call for (null), handle 139900452795104, injecting RTLD_NODELETE
Intercepted a dlopen call for /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/libzip.so, handle 89747636688000, injecting RTLD_NODELETE
Intercepted a dlopen call for /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/libnio.so, handle 89747636689536, injecting RTLD_NODELETE

没有 dlclose 行，并且没有任何句柄（转换为十六进制，不包括 nullptr 文件名的主程序）与<unknown module>s 中出现的地址范围匹配 - 可能与 ASLR 有关。最重要的是，<unknown module>s 仍然出现在 lsan 错误输出中，因此要么这种方法无法阻止卸载，要么问题不是由动态加载/卸载引起的。

我怎样才能找出哪些库对应于<unknown module>s？

java