[Bug libc/10652] New: getaddrinfo causes segfault if multithreaded and linked statically

["heuler at infosim dot net" <sourceware-bugzilla at sourceware dot org>]

The getaddrinfo call causes an internal segmentation fault when called from
threads and the binary is linked with "-static". The documentation says the
function is thread safe. This should be also the case when linked with "-static"
since there is no exception mentioned.
The crash only occurs if the binary is executed on a multi core system, on a
single core system it does not crash. This seems to be a synchronization problem
inside the library, but somehow only in the static version.

To reproduce just use this small test program:
#include <stdio.h>
#include <netdb.h>
#include <pthread.h>
#include <unistd.h>

void *test(void *)
{
        struct addrinfo *res = NULL;
        fprintf(stderr, "x=");
        int ret = getaddrinfo("localhost", NULL, NULL, &res);
        fprintf(stderr, "%d ", ret);
        return NULL;
}

int main()
{
        for (int i = 0; i < 512; i++)
        {
                pthread_t thr;
                pthread_create(&thr, NULL, test, NULL);
        }
        sleep(5);
        return 0;
}

Compile with "g++ -o dnstest -static dnstest.cpp -lpthread" and then start.
Usually when linked with "-static" it crashes immediately, without it works fine.
This was verified with different glibc versions from Fedore 7, 11, CentOS 5.3,
Ubuntu 8.x and 9.x, SuSE 11.1 32bit and 64bit.
The glibc versions tested are from 2.6 to 2.10.

I see no reason why this only works if dynamically linked. The documentation
also does not mention any restrictions if linked statically.

-- 
           Summary: getaddrinfo causes segfault if multithreaded and linked
                    statically
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: drepper at redhat dot com
        ReportedBy: heuler at infosim dot net
                CC: glibc-bugs at sources dot redhat dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=10652

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