* signal.c (rb_sigaltstack_size): new. calculate stack size for

  sigsegv handler. enlarge value when x86 or x86_64 on Linux.
  Linux has very small MINSIGSTKSZ size (2048 bytes) and
  our sigsegv routine need 5KiB at least. [Bug #7141]
* internal.h: add declaration of rb_sigaltstack_size().
* vm_core.h: remove ALT_STACK_SIZE definition.

* signal.c (rb_register_sigaltstack): replace ALT_STACK_SIZE with
  rb_sigaltstack_size();
* gc.c (Init_heap): ditto.
* vm.c (th_init): ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38409 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

6 files changed, 39 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index 27c746c766..2dd72299a3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+Sat Dec 15 23:08:56 2012  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* signal.c (rb_sigaltstack_size): new. calculate stack size for
+	  sigsegv handler. enlarge value when x86 or x86_64 on Linux.
+	  Linux has very small MINSIGSTKSZ size (2048 bytes) and
+	  our sigsegv routine need 5KiB at least. [Bug #7141]
+	* internal.h: add declaration of rb_sigaltstack_size().
+	* vm_core.h: remove ALT_STACK_SIZE definition.
+
+	* signal.c (rb_register_sigaltstack): replace ALT_STACK_SIZE with
+	  rb_sigaltstack_size();
+	* gc.c (Init_heap): ditto.
+	* vm.c (th_init): ditto.
+
 Sat Dec 15 18:24:21 2012  Tadayoshi Funaba  <tadf@dotrb.org>
 
 	* rational.c (f_round_common): should check overflow.
diff --git a/gc.c b/gc.c
index 4c5e2b48a8..c87526d016 100644
--- a/gc.c
+++ b/gc.c
@@ -574,7 +574,7 @@ init_heap(rb_objspace_t *objspace)
 	/* altstack of another threads are allocated in another place */
 	rb_thread_t *th = GET_THREAD();
 	void *tmp = th->altstack;
-	th->altstack = malloc(ALT_STACK_SIZE);
+	th->altstack = malloc(rb_sigaltstack_size());
 	free(tmp); /* free previously allocated area */
     }
 #endif
diff --git a/internal.h b/internal.h
index b069f67bb1..4ae0edf4b6 100644
--- a/internal.h
+++ b/internal.h
@@ -252,6 +252,7 @@ VALUE rb_reg_check_preprocess(VALUE);
 
 /* signal.c */
 int rb_get_next_signal(void);
+int rb_sigaltstack_size(void);
 
 /* strftime.c */
 #ifdef RUBY_ENCODING_H
diff --git a/signal.c b/signal.c
index 59ffde93db..44cb8e713e 100644
--- a/signal.c
+++ b/signal.c
@@ -447,6 +447,27 @@ typedef RETSIGTYPE ruby_sigaction_t(int);
 #endif
 
 #ifdef USE_SIGALTSTACK
+int rb_sigaltstack_size(void)
+{
+    /* XXX: BSD_vfprintf() uses >1500KiB stack and x86-64 need >5KiB stack. */
+    int size = 8192;
+
+#ifdef MINSIGSTKSZ
+    if (size < MINSIGSTKSZ)
+	size = MINSIGSTKSZ;
+#endif
+#if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
+    {
+	int pagesize;
+	pagesize = sysconf(_SC_PAGE_SIZE);
+	if (size < pagesize)
+	    size = pagesize;
+    }
+#endif
+
+    return size;
+}
+
 /* alternate stack for SIGSEGV */
 void
 rb_register_sigaltstack(rb_thread_t *th)
@@ -457,7 +478,7 @@ rb_register_sigaltstack(rb_thread_t *th)
 	rb_bug("rb_register_sigaltstack: th->altstack not initialized\n");
 
     newSS.ss_sp = th->altstack;
-    newSS.ss_size = ALT_STACK_SIZE;
+    newSS.ss_size = rb_sigaltstack_size();
     newSS.ss_flags = 0;
 
     sigaltstack(&newSS, &oldSS); /* ignore error. */
diff --git a/vm.c b/vm.c
index da15fd2675..2266754fc7 100644
--- a/vm.c
+++ b/vm.c
@@ -1834,7 +1834,7 @@ th_init(rb_thread_t *th, VALUE self)
     /* allocate thread stack */
 #ifdef USE_SIGALTSTACK
     /* altstack of main thread is reallocated in another place */
-    th->altstack = malloc(ALT_STACK_SIZE);
+    th->altstack = malloc(rb_sigaltstack_size());
 #endif
     th->stack_size = RUBY_VM_THREAD_STACK_SIZE;
     th->stack = thread_recycle_stack(th->stack_size);
diff --git a/vm_core.h b/vm_core.h
index 73b24a1e0e..8cc48bc00d 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -456,12 +456,6 @@ struct rb_unblock_callback {
 
 struct rb_mutex_struct;
 
-#ifdef MINSIGSTKSZ
-#define ALT_STACK_SIZE (MINSIGSTKSZ*2)
-#else
-#define ALT_STACK_SIZE (4*1024)
-#endif
-
 struct rb_thread_struct;
 typedef struct rb_thread_list_struct{
     struct rb_thread_list_struct *next;