Question

我有一个非常小的.so文件（此处可用：https://docs.google.com/leaf?id=0B4MxFm-ACB3INjhkMjhlNzktYzkxYy00Zjk5LTk0Y2MtZDE2MWQ2MzY1OWUy&hl=en_US&authkey=CMrJguwN）

我正在尝试将此加载到RHEL上的Java中，而Java main只是冻结（没有错误或异常）。我在LD_LIBRARY_PATH上有.so文件的目录，所以我知道它实际上是在尝试加载它。

我有什么想法可以解决这个问题吗？

public class SmallTester {


    public static void main(String[] args){

        for(String s: System.getenv("LD_LIBRARY_PATH").split(":")){
            System.out.println(s);
        }

        System.loadLibrary("TestAda");

        System.out.println("Here");
    }
}

编辑：

基于下面的帖子，我做了一个strace ..看起来它一遍又一遍地重复这个调用（我不确定这意味着什么？）：

[pid 31464] clock_gettime(CLOCK_MONOTONIC, {3605675, 624255544}) = 0
[pid 31464] gettimeofday({1306417113, 168967}, NULL) = 0
[pid 31464] clock_gettime(CLOCK_MONOTONIC, {3605675, 624435576}) = 0
[pid 31464] clock_gettime(CLOCK_MONOTONIC, {3605675, 624518205}) = 0
[pid 31464] gettimeofday({1306417113, 169216}, NULL) = 0
[pid 31464] clock_gettime(CLOCK_REALTIME, {1306417113, 169306590}) = 0
[pid 31464] futex(0x88b3f04, FUTEX_WAIT_PRIVATE, 1, {0, 49909410}) = -1 ETIMEDOUT (Connection timed out)

以下是日志的完整版本：https://docs.google.com/leaf?id=0B4MxFm-ACB3IYzdhZWIwNWEtYjUzMS00NGM5LWEzZjQtYzMzOWE3MWNhYWQ0&hl=en_US&authkey=CJ-Lv_wG

EDIT2：我也试图用JNA加载库：

public class SmallTesterJNA {

    public interface CLibrary extends Library {

      CLibrary INSTANCE1 = (CLibrary)
      Native.loadLibrary("TestAda", //  <<< our library goes here
                         CLibrary.class);

    }

    public static void main(String[] args){

        for(String s: System.getenv("LD_LIBRARY_PATH").split(":")){
            System.out.println(s);
        }

        System.loadLibrary(CLibrary.INSTANCE1.toString());

        System.out.println("Here");
    }
}

这是输出..它看起来非常相似：https://docs.google.com/leaf?id=0B4MxFm-ACB3IYzdhZWIwNWEtYjUzMS00NGM5LWEzZjQtYzMzOWE3MWNhYWQ0&hl=en_US&authkey=CJ-Lv_wG

EDIT2：

这是我的gcore输出附加到进程..不知道这是告诉我的：

(no debugging symbols found)
(no debugging symbols found)
[Thread debugging using libthread_db enabled]
[New Thread 0xb7fb26c0 (LWP 8326)]
[New Thread 0x7fa8eb90 (LWP 8340)]
[New Thread 0x7fe2db90 (LWP 8339)]
[New Thread 0x7fe7eb90 (LWP 8338)]
[New Thread 0x7feffb90 (LWP 8337)]
[New Thread 0x800afb90 (LWP 8336)]
[New Thread 0x80100b90 (LWP 8335)]
[New Thread 0x80351b90 (LWP 8334)]
[New Thread 0x803a2b90 (LWP 8333)]
[New Thread 0x80423b90 (LWP 8332)]
[New Thread 0x8066db90 (LWP 8331)]
[New Thread 0x806eeb90 (LWP 8330)]
[New Thread 0x8076fb90 (LWP 8329)]
[New Thread 0x807f0b90 (LWP 8328)]
[New Thread 0xb7474b90 (LWP 8327)]
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
0xb7fcd402 in __kernel_vsyscall ()
Saved corefile core.8326

Answer 1

如果我不得不猜测，我会说可能的罪魁祸首是共享对象的初始化代码。

获取JVM进程的核心转储（使用gcore）或附加gdb以获取堆栈跟踪的确切位置。

Answer 2

我通常在gdb之前尝试strace（跟踪所有系统调用）。执行：

strace -f java SmallTester > logfile 2>&1

您将在 logfile 中获得大量信息，最后一部分是最有趣的。你会发现jvm进程正在寻找你的TestAda.so文件，看看它是否成功加载了.so文件。如果这不起作用，请恢复为gdb。

Answer 3

查看C ++代码中的JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *reserved)函数。它可能有一个无限循环:)如果它还没有定义，也尝试定义它。

有关JNI_OnLoad的详细信息，请参阅here。

Linux上的Java System.loadLibrary调用冻结

3 个答案: