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-rw-r--r--mysql-stack-guard.patch139
1 files changed, 139 insertions, 0 deletions
diff --git a/mysql-stack-guard.patch b/mysql-stack-guard.patch
new file mode 100644
index 0000000..c01c1a7
--- /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 -up mysql-5.5.28/sql/mysqld.cc.p5 mysql-5.5.28/sql/mysqld.cc
+--- mysql-5.5.28/sql/mysqld.cc.p5 2012-08-29 10:50:46.000000000 +0200
++++ mysql-5.5.28/sql/mysqld.cc 2012-12-06 14:13:59.765407494 +0100
+@@ -2599,6 +2599,70 @@ static void init_signals(void)
+ }
+
+
++/* 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;
+@@ -2609,15 +2673,7 @@ static void start_signal_handler(void)
+ #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);
+@@ -4398,36 +4454,8 @@ int mysqld_main(int argc, char **argv)
+ 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