From: Russ Cox <rsc@golang.org>
Date: Wed, 20 Oct 2010 19:16:39 +0000 (-0700)
Subject: 6l: correct logic for morestack choice
X-Git-Tag: weekly.2010-10-20~10
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=c2b91d4889cf50abda0d55483f44f2d2cd5c5ad4;p=gostls13.git

6l: correct logic for morestack choice

The frame that gets allocated is for both
the args and the autos.  If together they
exceed the default frame size, we need to
tell morestack about both so that it allocates
a large enough frame.

Sanity check stack pointer in morestack
to catch similar bugs.

R=ken2
CC=golang-dev
https://golang.org/cl/2609041
---

diff --git a/src/cmd/6l/pass.c b/src/cmd/6l/pass.c
index a2a82a18b5..8dc0ed551b 100644
--- a/src/cmd/6l/pass.c
+++ b/src/cmd/6l/pass.c
@@ -469,7 +469,7 @@ dostkoff(void)
 
 			/* 160 comes from 3 calls (3*8) 4 safes (4*8) and 104 guard */
 			moreconst1 = 0;
-			if(autoffset+160 > 4096)
+			if(autoffset+160+textarg > 4096)
 				moreconst1 = (autoffset+160) & ~7LL;
 			moreconst2 = textarg;
 
diff --git a/src/pkg/runtime/proc.c b/src/pkg/runtime/proc.c
index d898b30b37..b07b6d67c4 100644
--- a/src/pkg/runtime/proc.c
+++ b/src/pkg/runtime/proc.c
@@ -749,6 +749,8 @@ newstack(void)
 	args = m->moreargs;
 	g1 = m->curg;
 
+	if(m->morebuf.sp < g1->stackguard - StackGuard)
+		throw("split stack overflow");
 
 	if(frame == 1 && args > 0 && m->morebuf.sp - sizeof(Stktop) - args - 32 > g1->stackguard) {
 		// special case: called from reflect.call (frame == 1)