glibc 2.3.2: dlopen(libpthread.so) segfaults

[Patrick Smith]

This occurred during 'make check' while I was trying to install glibc 
2.3.2 in the following environment:

PowerPC (G4)
Linux kernel 2.4.20
gcc 3.2.2
binutils 2.13.90.0.18

configure options:  --prefix=... --libexecdir=... --enable-add-ons
                    --with-headers=... --without-gd
                    --enable-kernel=2.4.8 --enable-static-nss

In 'make check', bug-iconv3 died with a segmentation violation while in 
the call 'dlopen (LIBPTHREAD_SO, RTLD_NOW)'.  A small test program that 
did just that one function call also died with a segmentation violation.

The crash was happening near the end of pthread_initialize() in 
pthread.c, at the line

        *__libc_dl_error_tsd () = *(*GL(dl_error_catch_tsd)) ();

Apparently, __libc_dl_error_tsd was returning a bad pointer, so the 
store to that address caused a segfault.

I noticed that __pthread_initialize_minimal wasn't ever called, and 
tried modifying pthread_initialize to call it (plus added a check in 
__pthread_initialize_minimal to return without doing anything if this 
isn't the first call).  This seems to fix the problem, though I don't 
know if it could cause other problems.

A patch showing this change is attached.

--- linuxthreads/pthread.c.orig 2003-01-16 13:14:41.000000000 -0500
+++ linuxthreads/pthread.c      2003-04-02 22:42:15.000000000 -0500
@@ -294,7 +294,15 @@
 {
 #ifdef USE_TLS
   pthread_descr self;
+#endif
+
+  static int first_time = 1;
+  if (first_time)
+     first_time = 0;
+  else
+     return;
 
+#ifdef USE_TLS
   /* First of all init __pthread_handles[0] and [1] if needed.  */
 # if __LT_SPINLOCK_INIT != 0
   __pthread_handles[0].h_lock = __LOCK_INITIALIZER;
@@ -467,6 +475,8 @@
   struct sigaction sa;
   sigset_t mask;
 
+  __pthread_initialize_minimal();
+
   /* If already done (e.g. by a constructor called earlier!), bail out */
   if (__pthread_initial_thread_bos != NULL) return;
 #ifdef TEST_FOR_COMPARE_AND_SWAP