Fix for Bug#27970 "Fix for bug 24507 makes mysql_install_db fail"

include/my_pthread.h:
  Fix for Bug#27970 "Fix for bug 24507 makes mysql_install_db fail".
  
  Removed macro NPTL_PTHREAD_EXIT_BUG, because it doesn't work in dynamic
  environment. One can switch between NPTL and LT on the fly on Linux.
  
  Added pthread_dummy(ESRCH) for those platforms that don't have pthread_kill.
  This ensures that there won't be an error in mysqld.cc where the return value 
  is being checked from the function call.
mysys/my_thr_init.c:
  Check for a Linux is enough. There is an additional test if
  NPTL is in use before spwaning the extra thread.

include/my_pthread.h

@@ -30,25 +30,6 @@ extern "C" {
 #define EXTERNC
 #endif /* __cplusplus */ 
 
-/*
-  BUG#24507: Race conditions inside current NPTL pthread_exit() implementation.
-  
-  If macro NPTL_PTHREAD_EXIT_HACK is defined then a hack described in the bug
-  report will be implemented inside my_thread_global_init() in my_thr_init.c.
-   
-  This amounts to spawning a dummy thread which does nothing but executes 
-  pthread_exit(0). 
-  
-  This bug is fixed in version 2.5 of glibc library.
-  
-  TODO: Remove this code when fixed versions of glibc6 are in common use. 
- */
-
-#if defined(TARGET_OS_LINUX) && defined(HAVE_NPTL) && \
-    defined(__GLIBC__) && ( __GLIBC__ < 2 || __GLIBC__ == 2 && __GLIBC_MINOR__ < 5 )
-#define NPTL_PTHREAD_EXIT_BUG	1
-#endif 
-
 #if defined(__WIN__) || defined(OS2)
 
 #ifdef OS2
@@ -199,7 +180,7 @@ extern int pthread_mutex_destroy (pthread_mutex_t *);
 #define pthread_mutex_unlock(A)  LeaveCriticalSection(A)
 #define pthread_mutex_destroy(A) DeleteCriticalSection(A)
 #define my_pthread_setprio(A,B)  SetThreadPriority(GetCurrentThread(), (B))
-#define pthread_kill(A,B) pthread_dummy(0)
+#define pthread_kill(A,B) pthread_dummy(ESRCH)
 #endif /* OS2 */
 
 /* Dummy defines for easier code */
@@ -463,14 +444,14 @@ struct tm *gmtime_r(const time_t *clock, struct tm *res);
 #define pthread_attr_setdetachstate(A,B) pthread_dummy(0)
 #define pthread_create(A,B,C,D) pthread_create((A),*(B),(C),(D))
 #define pthread_sigmask(A,B,C) sigprocmask((A),(B),(C))
-#define pthread_kill(A,B) pthread_dummy(0)
+#define pthread_kill(A,B) pthread_dummy(ESRCH)
 #undef	pthread_detach_this_thread
 #define pthread_detach_this_thread() { pthread_t tmp=pthread_self() ; pthread_detach(&tmp); }
 #endif
 
 #ifdef HAVE_DARWIN5_THREADS
 #define pthread_sigmask(A,B,C) sigprocmask((A),(B),(C))
-#define pthread_kill(A,B) pthread_dummy(0)
+#define pthread_kill(A,B) pthread_dummy(ESRCH)
 #define pthread_condattr_init(A) pthread_dummy(0)
 #define pthread_condattr_destroy(A) pthread_dummy(0)
 #undef	pthread_detach_this_thread
@@ -490,7 +471,7 @@ struct tm *gmtime_r(const time_t *clock, struct tm *res);
 #ifndef pthread_sigmask
 #define pthread_sigmask(A,B,C) sigprocmask((A),(B),(C))
 #endif
-#define pthread_kill(A,B) pthread_dummy(0)
+#define pthread_kill(A,B) pthread_dummy(ESRCH)
 #undef	pthread_detach_this_thread
 #define pthread_detach_this_thread() { pthread_t tmp=pthread_self() ; pthread_detach(&tmp); }
 #elif !defined(__NETWARE__) /* HAVE_PTHREAD_ATTR_CREATE && !HAVE_SIGWAIT */
@@ -717,6 +698,11 @@ extern pthread_mutexattr_t my_errorcheck_mutexattr;
 #define MY_MUTEX_INIT_ERRCHK   NULL
 #endif
 
+#ifndef ESRCH
+/* Define it to something */
+#define ESRCH 1
+#endif
+
 extern my_bool my_thread_global_init(void);
 extern void my_thread_global_end(void);
 extern my_bool my_thread_init(void);

mysys/my_thr_init.c

@@ -47,7 +47,7 @@ pthread_mutexattr_t my_fast_mutexattr;
 pthread_mutexattr_t my_errorcheck_mutexattr;
 #endif
 
-#ifdef NPTL_PTHREAD_EXIT_BUG /* see my_pthread.h */
+#ifdef TARGET_OS_LINUX
 
 /*
  Dummy thread spawned in my_thread_global_init() below to avoid
@@ -62,7 +62,7 @@ nptl_pthread_exit_hack_handler(void *arg __attribute__((unused)))
   return 0;
 }
 
-#endif
+#endif /* TARGET_OS_LINUX */
 
 static uint get_thread_lib(void);
 
@@ -88,7 +88,7 @@ my_bool my_thread_global_init(void)
     return 1;
   }
 
-#ifdef NPTL_PTHREAD_EXIT_BUG
+#ifdef TARGET_OS_LINUX
   /*
     BUG#24507: Race conditions inside current NPTL pthread_exit()
     implementation.
@@ -112,7 +112,7 @@ my_bool my_thread_global_init(void)
     pthread_create(&dummy_thread,&dummy_thread_attr,
                    nptl_pthread_exit_hack_handler, NULL);
   }
-#endif
+#endif /* TARGET_OS_LINUX */
 
 #ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
   /*
@@ -178,10 +178,17 @@ void my_thread_global_end(void)
                                       &abstime);
     if (error == ETIMEDOUT || error == ETIME)
     {
+#ifdef HAVE_PTHREAD_KILL
+      /*
+        We shouldn't give an error here, because if we don't have
+        pthread_kill(), programs like mysqld can't ensure that all threads
+        are killed when we enter here.
+      */
       if (THR_thread_count)
         fprintf(stderr,
                 "Error in my_thread_global_end(): %d threads didn't exit\n",
                 THR_thread_count);
+#endif
       all_threads_killed= 0;
       break;
     }
@@ -206,7 +213,7 @@ void my_thread_global_end(void)
   if (all_threads_killed)
   {
     pthread_mutex_destroy(&THR_LOCK_threads);
-    pthread_cond_destroy (&THR_COND_threads);
+    pthread_cond_destroy(&THR_COND_threads);
   }
 #if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)
   pthread_mutex_destroy(&LOCK_localtime_r);

sql/mysqld.cc

@@ -1233,7 +1233,7 @@ static void wait_for_signal_thread_to_end()
   */
   for (i= 0 ; i < 100 && signal_thread_in_use; i++)
   {
-    if (pthread_kill(signal_thread, MYSQL_KILL_SIGNAL))
+    if (pthread_kill(signal_thread, MYSQL_KILL_SIGNAL) != ESRCH)
       break;
     my_sleep(100);				// Give it time to die
   }