From 5731cfe7c0f07bf655dffd9c065398090daa14cb Mon Sep 17 00:00:00 2001
From: Remi Collet <fedora@famillecollet.com>
Date: Fri, 15 Apr 2011 16:58:14 +0200
Subject: prepare compat-mysql55

---
 mysql-stack-guard.patch | 139 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 139 insertions(+)
 create mode 100644 mysql-stack-guard.patch

(limited to 'mysql-stack-guard.patch')

diff --git a/mysql-stack-guard.patch b/mysql-stack-guard.patch
new file mode 100644
index 0000000..0634560
--- /dev/null
+++ b/mysql-stack-guard.patch
@@ -0,0 +1,139 @@
+mysql is not accounting for the "guard page" when setting thread stack size
+requests.  This is fatal on PPC systems, which may use guard pages as large
+as 64K.  This patch also documents the IA64 situation a bit better.
+
+Note: there are quite a few other setstacksize calls besides the two in
+mysqld.cc; is it important to fix any of the others?
+
+Filed upstream at http://bugs.mysql.com/bug.php?id=35019
+
+
+diff -Naur mysql-5.5.8.orig/sql/mysqld.cc mysql-5.5.8/sql/mysqld.cc
+--- mysql-5.5.8.orig/sql/mysqld.cc	2010-12-03 12:58:26.000000000 -0500
++++ mysql-5.5.8/sql/mysqld.cc	2010-12-20 22:01:08.939186906 -0500
+@@ -2602,6 +2602,70 @@
+ }
+ 
+ 
++/* pthread_attr_setstacksize without so much platform-dependency */
++/* returns the actual stack size if possible */
++static size_t my_setstacksize(pthread_attr_t *attr, size_t stacksize)
++{
++  size_t guard_size = 0;
++
++#if defined(__ia64__) || defined(__ia64)
++  /*
++    On IA64, half of the requested stack size is used for "normal stack"
++    and half for "register stack".  The space measured by check_stack_overrun
++    is the "normal stack", so double the request to make sure we have the
++    caller-expected amount of normal stack.
++
++    NOTE: there is no guarantee that the register stack can't grow faster
++    than normal stack, so it's very unclear that we won't dump core due to
++    stack overrun despite check_stack_overrun's efforts.  Experimentation
++    shows that in the execution_constants test, the register stack grows
++    less than half as fast as normal stack, but perhaps other scenarios are
++    less forgiving.  If it turns out that more space is needed for the
++    register stack, that could be forced (rather inefficiently) by using a
++    multiplier higher than 2 here.
++  */
++  stacksize *= 2;
++#endif
++
++  /*
++    On many machines, the "guard space" is subtracted from the requested
++    stack size, and that space is quite large on some platforms.  So add
++    it to our request, if we can find out what it is.
++
++    FIXME: autoconfiscate use of pthread_attr_getguardsize
++  */
++  if (pthread_attr_getguardsize(attr, &guard_size))
++    guard_size = 0;		/* if can't find it out, treat as 0 */
++
++  pthread_attr_setstacksize(attr, stacksize + guard_size);
++
++  /* Retrieve actual stack size if possible */
++#ifdef HAVE_PTHREAD_ATTR_GETSTACKSIZE
++  {
++    size_t real_stack_size= 0;
++    /* We must ignore real_stack_size = 0 as Solaris 2.9 can return 0 here */
++    if (pthread_attr_getstacksize(attr, &real_stack_size) == 0 &&
++	real_stack_size > guard_size)
++    {
++      real_stack_size -= guard_size;
++      if (real_stack_size < stacksize)
++      {
++	if (global_system_variables.log_warnings)
++	  sql_print_warning("Asked for %ld thread stack, but got %ld",
++			    (long) stacksize, (long) real_stack_size);
++	stacksize= real_stack_size;
++      }
++    }
++  }
++#endif
++
++#if defined(__ia64__) || defined(__ia64)
++  stacksize /= 2;
++#endif
++  return stacksize;
++}
++
++
+ static void start_signal_handler(void)
+ {
+   int error;
+@@ -2612,15 +2676,7 @@
+ #if !defined(HAVE_DEC_3_2_THREADS)
+   pthread_attr_setscope(&thr_attr,PTHREAD_SCOPE_SYSTEM);
+   (void) pthread_attr_setdetachstate(&thr_attr,PTHREAD_CREATE_DETACHED);
+-#if defined(__ia64__) || defined(__ia64)
+-  /*
+-    Peculiar things with ia64 platforms - it seems we only have half the
+-    stack size in reality, so we have to double it here
+-  */
+-  pthread_attr_setstacksize(&thr_attr,my_thread_stack_size*2);
+-#else
+-  pthread_attr_setstacksize(&thr_attr,my_thread_stack_size);
+-#endif
++  (void) my_setstacksize(&thr_attr,my_thread_stack_size);
+ #endif
+ 
+   mysql_mutex_lock(&LOCK_thread_count);
+@@ -4361,36 +4417,8 @@
+     unireg_abort(1);				// Will do exit
+ 
+   init_signals();
+-#if defined(__ia64__) || defined(__ia64)
+-  /*
+-    Peculiar things with ia64 platforms - it seems we only have half the
+-    stack size in reality, so we have to double it here
+-  */
+-  pthread_attr_setstacksize(&connection_attrib,my_thread_stack_size*2);
+-#else
+-  pthread_attr_setstacksize(&connection_attrib,my_thread_stack_size);
+-#endif
+ #ifdef HAVE_PTHREAD_ATTR_GETSTACKSIZE
+-  {
+-    /* Retrieve used stack size;  Needed for checking stack overflows */
+-    size_t stack_size= 0;
+-    pthread_attr_getstacksize(&connection_attrib, &stack_size);
+-#if defined(__ia64__) || defined(__ia64)
+-    stack_size/= 2;
+-#endif
+-    /* We must check if stack_size = 0 as Solaris 2.9 can return 0 here */
+-    if (stack_size && stack_size < my_thread_stack_size)
+-    {
+-      if (global_system_variables.log_warnings)
+-	sql_print_warning("Asked for %lu thread stack, but got %ld",
+-			  my_thread_stack_size, (long) stack_size);
+-#if defined(__ia64__) || defined(__ia64)
+-      my_thread_stack_size= stack_size*2;
+-#else
+-      my_thread_stack_size= stack_size;
+-#endif
+-    }
+-  }
++  my_thread_stack_size = my_setstacksize(&connection_attrib,my_thread_stack_size);
+ #endif
+ 
+   (void) thr_setconcurrency(concurrency);	// 10 by default
-- 
cgit