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?
My command line:
g++ -Wall -g main.cpp -lglut -lGL -lGLU -o main
My simple test case:
#include
#include
#include
#include
#include
int main(int argc, char** argv){
printf("Started\n");
std::string dummy = "hello";
glutInit(&argc, argv);
return 0;
}
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 , args=args@entry=0x7fffffffddf0) at dlerror.c:129
#3 0x00007ffff3488198 in __dlsym (handle=, name=) 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=, argv=, argc=, l=) 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 ?? ()
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.
Edit: I have tried gmbeard's suggestions. Turining off optimizations (-O0) didn't change anything about the callstack produced by gdb.
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)
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)
But a quick glance doesn't reveal anything amiss.
Answer
So you see in the LD_DEBUG output:
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]
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].
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
in order to make sure that pthread_key_create is loaded before other symbols.
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 , args=args@entry=0x7fffffffddf0) at dlerror.c:129
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:
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);
(frame #1):
/* 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;
}
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)
I asked you to build with:
g++ -pthread -Wall -g main.cpp -lpthread -lglut -lGL -lGLU -o main
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
For example you can add disasemble for frame #1 to your question
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