使用 glut 和 std::string 时 main() 之前的分段错误?-C/C++问题

Segmentation Fault before main() when using glut, and std::string?(使用 glut 和 std::string 时 main() 之前的分段错误?)

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问题描述

在 64 位 Ubuntu 14.04 LTS 上，我试图编译一个使用 glut 的简单 OpenGL 程序.在 main 中执行任何代码行之前，我收到了一个分段错误 (SIGSEV)；即使在一个非常精简的测试程序中.什么可能导致这种情况?

On 64-bit Ubuntu 14.04 LTS, I am trying to compile a simple OpenGL program that uses glut. I am getting a Segmentation Fault (SIGSEV) before any line of code is executed in main; even on a very stripped down test program. What could cause this?

我的命令行:

g++ -Wall -g main.cpp -lglut -lGL -lGLU -o main

我的简单测试用例:

#include <GL/gl.h>                                                                                                                                         
#include <GL/glu.h>
#include <GL/glut.h>

#include <string>
#include <cstdio>

int main(int argc, char** argv){
    printf("Started
");                                                                                                   
    std::string dummy = "hello";
    glutInit(&argc, argv);
    return 0;
}

当我运行程序时，main 开头的 printf 在段错误之前无法执行.在 GDB 下，我在段错误之后得到了这个回溯

When I run the program, the printf at the beginning of main doesn't get to execute before the segfault. Under GDB, I get this back trace after the segfault is

#0  0x0000000000000000 in ?? ()
#1  0x00007ffff3488291 in init () at dlerror.c:177
#2  0x00007ffff34886d7 in _dlerror_run (operate=operate@entry=0x7ffff3488130 <dlsym_doit>, args=args@entry=0x7fffffffddf0) at dlerror.c:129
#3  0x00007ffff3488198 in __dlsym (handle=<optimized out>, name=<optimized out>) at dlsym.c:70
#4  0x00007ffff702628e in ?? () from /usr/lib/nvidia-352/libGL.so.1
#5  0x00007ffff6fd1aa7 in ?? () from /usr/lib/nvidia-352/libGL.so.1
#6  0x00007ffff7dea0fd in call_init (l=0x7ffff7fd39c8, argc=argc@entry=1, argv=argv@entry=0x7fffffffdf48, env=env@entry=0x7fffffffdf58) at dl-init.c:64
#7  0x00007ffff7dea223 in call_init (env=<optimized out>, argv=<optimized out>, argc=<optimized out>, l=<optimized out>) at dl-init.c:36
#8  _dl_init (main_map=0x7ffff7ffe1c8, argc=1, argv=0x7fffffffdf48, env=0x7fffffffdf58) at dl-init.c:126
#9  0x00007ffff7ddb30a in _dl_start_user () from /lib64/ld-linux-x86-64.so.2
#10 0x0000000000000001 in ?? ()
#11 0x00007fffffffe2ba in ?? ()
#12 0x0000000000000000 in ?? ()

这是踢球者.如果我注释掉 gluInit 行或std::string 虚拟行，程序将编译并运行得很好.直到我注意到这一点，我才认为我的 GLUT 有问题(尽管我已经尝试了我正在调试的原始程序(我已经精简到这个例子))几个系统都没有成功.我在这里有点不知所措.

And here's the kicker. If I comment out either the gluInit line or the std::string dummy line, the program compiles and runs just fine. Up until I noticed this I assumed there was something wrong with my GLUT (though I've tried the original program I'm debugging on (that I stripped down to this example)) several systems with no success. I am at a bit of a loss here.

我已经尝试过 gmbeard 的建议.关闭优化 (-O0) 并没有改变 gdb 生成的调用堆栈.

I have tried gmbeard's suggestions. Turining off optimizations (-O0) didn't change anything about the callstack produced by gdb.

在程序上运行 ldd 给了我:

Running ldd on the program gives me:

linux-vdso.so.1 =>  (0x00007ffe3b7f1000)
libglut.so.3 => /usr/lib/x86_64-linux-gnu/libglut.so.3 (0x00007f04978fa000)
libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f04975f6000)
libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f04973e0000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f049701b000)
libGL.so.1 => /usr/lib/nvidia-352/libGL.so.1 (0x00007f0496cec000)
libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007f04969b7000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f04966b1000)
libXi.so.6 => /usr/lib/x86_64-linux-gnu/libXi.so.6 (0x00007f04964a1000)
libXxf86vm.so.1 => /usr/lib/x86_64-linux-gnu/libXxf86vm.so.1 (0x00007f049629b000)
/lib64/ld-linux-x86-64.so.2 (0x00007f0497b44000)
libnvidia-tls.so.352.21 => /usr/lib/nvidia-352/tls/libnvidia-tls.so.352.21 (0x00007f0496098000)
libnvidia-glcore.so.352.21 => /usr/lib/nvidia-352/libnvidia-glcore.so.352.21 (0x00007f0493607000)
libXext.so.6 => /usr/lib/x86_64-linux-gnu/libXext.so.6 (0x00007f04933f5000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f04931f1000)
libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007f0492fd2000)
libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007f0492dce000)
libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007f0492bc8000)

然后，确定了我使用的是哪个 libGL，我在它上面运行了 ldd

And then, having identified which libGL I am using, I ran ldd on it

linux-vdso.so.1 =>  (0x00007ffc55df8000)
libnvidia-tls.so.352.21 => /usr/lib/nvidia-352/tls/libnvidia-tls.so.352.21 (0x00007faa60d83000)
libnvidia-glcore.so.352.21 => /usr/lib/nvidia-352/libnvidia-glcore.so.352.21 (0x00007faa5e2f2000)
libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007faa5dfbd000)
libXext.so.6 => /usr/lib/x86_64-linux-gnu/libXext.so.6 (0x00007faa5ddab000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007faa5d9e6000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007faa5d7e2000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007faa5d4dc000)
libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007faa5d2bd000)
/lib64/ld-linux-x86-64.so.2 (0x00007faa612b5000)
libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007faa5d0b9000)
libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007faa5ceb3000)

但快速浏览并没有发现任何问题.

But a quick glance doesn't reveal anything amiss.

推荐答案

所以你在 LD_DEBUG 输出中看到:

So you see in the LD_DEBUG output:

它打印出来的最后一件事是:" 20863: symbol=__pthread_key_create;在 file=/usr/lib/x86_64-linux-gnu/libXdmcp.so.6 [0]

The last thing it prints out is: " 20863: symbol=__pthread_key_create; lookup in file=/usr/lib/x86_64-linux-gnu/libXdmcp.so.6 [0]

这意味着 ld.so id 正在寻找 __pthread_key_create 因为它是你的图书馆之一需要的 [并且你最好找到这个符号需要什么图书馆，它可能会回答什么图书馆需要libpthread.so].

It means that ld.so id looking for __pthread_key_create since it is needed by one of your librarie [and you'd better find what library is needed this symbol, it possibly will answer what library need libpthread.so].

所以 __pthread_key_create 必须在 libpthread.so 中，但你的 ldd 输出中没有 libpthread.so.正如您在下面看到的，您的程序可能在 init() 中使用 __pthread_key_create 时崩溃.顺便说一句，你也可以试试

So __pthread_key_create must be in libpthread.so but you have no libpthread.so in your ldd output. As you can see below your program crashes possibly in using __pthread_key_create in init(). By the way you can try also

LD_PRELOAD=/lib64/libpthread.so.0 ./main

为了确保pthread_key_create在其他符号之前加载.

in order to make sure that pthread_key_create is loaded before other symbols.

所以 lgut 不太可能成为问题.它只是在初始化时调用 dlsym，这是绝对正确的行为.但是程序崩溃了:

So lgut is unlikely to be a problem. It just calls dlsym in initialization and it is absolutely correct behaviour. But the program crashes:

#0  0x0000000000000000 in ?? ()
#1  0x00007ffff3488291 in init () at dlerror.c:177
#2  0x00007ffff34886d7 in _dlerror_run (operate=operate@entry=0x7ffff3488130 <dlsym_doit>, args=args@entry=0x7fffffffddf0) at dlerror.c:129

这个回溯显示调用了一个地址为 0x00000000 的函数(我猜它是 __pthread_key_create 的未解析地址)，这是一个错误.调用了什么函数?查看来源:

This backtrace shows that a function with 0x00000000 address (my guess it is yet unresolved address of __pthread_key_create) was called and that is an error. What function was called? Look at sources:

这是 dlerror.c:129(第 2 帧):

This is dlerror.c:129 (frame #2):

int
internal_function
_dlerror_run (void (*operate) (void *), void *args)
{
  struct dl_action_result *result;

  /* If we have not yet initialized the buffer do it now.  */
  __libc_once (once, init);

(第 1 帧):

/* Initialize buffers for results.  */
static void
init (void)
{
  if (__libc_key_create (&key, free_key_mem))
    /* Creating the key failed.  This means something really went
       wrong.  In any case use a static buffer which is better than
       nothing.  */
    static_buf = &last_result;
}

它必须是 __libc_key_create 是一个宏并且它在 glibc 中有不同的定义.如果您为 POSIX 构建它被定义

It must be __libc_key_create that is a macro and it has in glibc different definitions. If you build for POSIX it is defined

/* Create thread-specific key.  */
#define __libc_key_create(KEY, DESTRUCTOR) 
  __libc_ptf_call (__pthread_key_create, (KEY, DESTRUCTOR), 1)

我让你用:

g++ -pthread -Wall -g main.cpp -lpthread -lglut -lGL -lGLU -o main

为了确保__libc_key_create实际上调用了__pthread_key_create并且lpthread在-lglut之前被初始化.但是如果你不想使用 -pthread 那么你可能需要分析帧 #1

In order to make sure that __libc_key_create in fact calls __pthread_key_create and lpthread is initialized before -lglut. But if you do not want use -pthread then possibly you need to analyze frame #1

#1  0x00007ffff3488291 in init () at dlerror.c:177

例如，您可以将第 1 帧的反汇编添加到您的问题中

For example you can add disasemble for frame #1 to your question

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