From 9dee1c884eb50ba282eb9dd2495c5269add25963 Mon Sep 17 00:00:00 2001
From: Paul Eggert
Date: Fri, 14 Jul 2017 04:54:05 -0700
Subject: Improve stack-overflow heuristic on GNU/Linux

Problem reported by Steve Kemp (Bug#27585).
* src/eval.c (near_C_stack_top): Remove.  All uses replaced
by current_thread->stack_top.
(record_in_backtrace): Set current_thread->stack_top.
This is for when the Lisp interpreter calls itself.
* src/lread.c (read1): Set current_thread->stack_top.
This is for recursive s-expression reads.
* src/print.c (print_object): Set current_thread->stack_top.
This is for recursive s-expression printing.
* src/thread.c (mark_one_thread): Get stack top first.
* src/thread.h (struct thread_state.stack_top): Now void *, not char *.
---
 src/thread.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

(limited to 'src/thread.c')

diff --git a/src/thread.c b/src/thread.c
index e3787971a53..1f7ced386d3 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -595,14 +595,15 @@ thread_select (select_func *func, int max_fds, fd_set *rfds,
 static void
 mark_one_thread (struct thread_state *thread)
 {
-  struct handler *handler;
-  Lisp_Object tem;
+  /* Get the stack top now, in case mark_specpdl changes it.  */
+  void *stack_top = thread->stack_top;
 
   mark_specpdl (thread->m_specpdl, thread->m_specpdl_ptr);
 
-  mark_stack (thread->m_stack_bottom, thread->stack_top);
+  mark_stack (thread->m_stack_bottom, stack_top);
 
-  for (handler = thread->m_handlerlist; handler; handler = handler->next)
+  for (struct handler *handler = thread->m_handlerlist;
+       handler; handler = handler->next)
     {
       mark_object (handler->tag_or_ch);
       mark_object (handler->val);
@@ -610,6 +611,7 @@ mark_one_thread (struct thread_state *thread)
 
   if (thread->m_current_buffer)
     {
+      Lisp_Object tem;
       XSETBUFFER (tem, thread->m_current_buffer);
       mark_object (tem);
     }
-- 
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