From: Andrew Gerrand <adg@golang.org>
Date: Fri, 1 Nov 2013 00:21:54 +0000 (+1100)
Subject: [release-branch.go1.2] runtime: relax preemption assertion during stack split
X-Git-Tag: go1.2rc3~17
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=038ff9dca156c92527167dd15f6da918b6f91648;p=gostls13.git

[release-branch.go1.2] runtime: relax preemption assertion during stack split

««« CL 18740044 / 1a8903f0a577
runtime: relax preemption assertion during stack split

The case can happen when starttheworld is calling acquirep
to get things moving again and acquirep gets preempted.
The stack trace is in golang.org/issue/6644.

It is difficult to build a short test case for this, but
the person who reported issue 6644 confirms that this
solves the problem.

Fixes #6644.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/18740044
»»»

R=golang-dev
CC=golang-dev
https://golang.org/cl/20460044
---

diff --git a/src/pkg/runtime/stack.c b/src/pkg/runtime/stack.c
index 011c616bac..634706051c 100644
--- a/src/pkg/runtime/stack.c
+++ b/src/pkg/runtime/stack.c
@@ -255,7 +255,7 @@ runtime·newstack(void)
 	if(gp->stackguard0 == (uintptr)StackPreempt) {
 		if(gp == m->g0)
 			runtime·throw("runtime: preempt g0");
-		if(oldstatus == Grunning && m->p == nil)
+		if(oldstatus == Grunning && m->p == nil && m->locks == 0)
 			runtime·throw("runtime: g is running but p is not");
 		if(oldstatus == Gsyscall && m->locks == 0)
 			runtime·throw("runtime: stack split during syscall");