diff options
Diffstat (limited to 'mysql-stack-guard.patch')
| -rw-r--r-- | mysql-stack-guard.patch | 139 |
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 |