From: Ivan Maidanski <ivmai@mail.ru>
Date: Fri, 20 Jul 2012 20:36:34 +0000 (+0400)
Subject: Fix stop_info.stack_ptr assignment in GC_suspend_all for OpenBSD
X-Git-Tag: gc7_2d~1^2~6
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=e196288adb5f9579218746377f1237399f4789f9;p=gc

Fix stop_info.stack_ptr assignment in GC_suspend_all for OpenBSD
(commit '7ff92dc' from master branch)

* os_dep.c (GC_get_stack_base): Abort if pthread_stackseg_np fails
(if GC_OPENBSD_THREADS).
* pthread_stop_world.c (GC_suspend_all): Get correct stack_ptr by
calling pthread_stackseg_np (subtracting ss_size from ss_sp) instead
of retrieving it from OpenBSD pthread implementation-dependent context
(if GC_OPENBSD_THREADS); remove comment.
---

diff --git a/os_dep.c b/os_dep.c
index 333421d4..d9d8fdae 100644
--- a/os_dep.c
+++ b/os_dep.c
@@ -1304,7 +1304,8 @@ GC_INNER word GC_page_size = 0;
   GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb)
   {
     stack_t stack;
-    pthread_stackseg_np(pthread_self(), &stack);
+    if (pthread_stackseg_np(pthread_self(), &stack))
+      ABORT("pthread_stackseg_np(self) failed");
     sb->mem_base = stack.ss_sp;
     return GC_SUCCESS;
   }
diff --git a/pthread_stop_world.c b/pthread_stop_world.c
index 811cfb5a..20f54f97 100644
--- a/pthread_stop_world.c
+++ b/pthread_stop_world.c
@@ -446,15 +446,14 @@ STATIC int GC_suspend_all(void)
 #           endif
 
 #           ifdef GC_OPENBSD_THREADS
-              if (pthread_suspend_np(p -> id) != 0)
-                ABORT("pthread_suspend_np failed");
-              /* This will only work for userland pthreads.  It will    */
-              /* fail badly on rthreads.  Perhaps we should consider    */
-              /* a pthread_sp_np() function that returns the stack      */
-              /* pointer for a suspended thread and implement in both   */
-              /* pthreads and rthreads.                                 */
-              p -> stop_info.stack_ptr =
-                        *(ptr_t *)((char *)p -> id + UTHREAD_SP_OFFSET);
+              {
+                stack_t stack;
+                if (pthread_suspend_np(p -> id) != 0)
+                  ABORT("pthread_suspend_np failed");
+                if (pthread_stackseg_np(p->id, &stack))
+                  ABORT("pthread_stackseg_np failed");
+                p -> stop_info.stack_ptr = (ptr_t)stack.ss_sp - stack.ss_size;
+              }
 #           else
 #             ifndef PLATFORM_ANDROID
                 result = pthread_kill(p -> id, SIG_SUSPEND);