Re: popen/pthread/static-libs bug

[David Durham]

Davy Durham wrote:

>   Hi, I've found a combination of threads, popen and linking with 
> glibc statically which causes the application to lock up...
> My machine is using x86 linux-2.4.18 and glibc-2.2.4 .  I'm using 
> mandrake.. I've tried it on a debian machine running a 2.2 kernel and 
> also even on an alpha running linux and the problem happens there too..
>   I found this while trying to build a statically linked binary of my 
> application ReZound: http://rezound.sourceforge.net
>
> I've narrowed it down to a few source code lines which I have attached 
> as bug.c
>
> Basically, if you compile this as:
>
>     gcc -o bug bug.c -lpthread
>
> it will work., but if you compile the same thing as:
>
>     gcc -static -o bug bug.c -lpthread
>
> it will lock up..
>
> Now.. if you remove either the call to popen or the call to the two 
> thread functions it will work when gcc is given -static
>
> (And I know the FILE * from popen needs to be closed.. but it makes no 
> difference as the the problem happening whether I close it before the 
> thread starts or not)
>
> The fact that it's related to -static (which BTW tells gcc to use 
> static libraries instead of dynamic libraries for linking) may 
> indicate that it's just a packaging problem, or that it's related to 
> something with dynamic library function calls.
>
> Anyway, I hope this could be fixed soon... Even if everyone else in 
> the world doesn't upgrade glibc, I will, so the standalone app could 
> actually run.
>
> Please reply to my email address because I can't find anywhere on the 
> glibc www site to actually subscribe to this mailing list..
>
> Thanks,
>   Davy
>
> ------------------------------------------------------------------------
>
> #include <stdio.h>
> #include <pthread.h>
>
> void *func(void *temp)
> {
>         return NULL;
> }
>
> int main()
> {
>         pthread_t threadID;
>         void *status;
>
>         popen("ls","r");
>
>         pthread_create(&threadID,NULL,func,NULL);
>         pthread_join(threadID,&status);
>         
>         return 0;
> }
>  

Actually.. this source code can even be reduced to (I don't know why I 
had the pthread_join in there.. it hangs at the pthread_create):

#include <stdio.h>
#include <pthread.h>

void *func(void *temp)
{
        return NULL;
}

int main()
{
        pthread_t threadID;

        popen("ls","r");

        pthread_create(&threadID,NULL,func,NULL);
        
        return 0;
}