From: Russ Cox <rsc@golang.org>
Date: Fri, 20 Nov 2015 19:02:33 +0000 (-0500)
Subject: [release-branch.go1.5] runtime: fix new stack barrier check
X-Git-Tag: go1.5.2~19
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=7ab4cba9ad76f8853f11de1a72ff1db790c5ea61;p=gostls13.git

[release-branch.go1.5] runtime: fix new stack barrier check

During a crash showing goroutine stacks of all threads
(with GOTRACEBACK=crash), it can be that f == nil.

Only happens on Solaris; not sure why.

Change-Id: Iee2c394a0cf19fa0a24f6befbc70776b9e42d25a
Reviewed-on: https://go-review.googlesource.com/17110
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-on: https://go-review.googlesource.com/17122
Reviewed-by: Russ Cox <rsc@golang.org>
---

diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go
index aed6cbd694..8f27ba4d66 100644
--- a/src/runtime/traceback.go
+++ b/src/runtime/traceback.go
@@ -188,7 +188,7 @@ func gentraceback(pc0, sp0, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max in
 	}
 
 	f := findfunc(frame.pc)
-	if f.entry == stackBarrierPC {
+	if f != nil && f.entry == stackBarrierPC {
 		// We got caught in the middle of a stack barrier
 		// (presumably by a signal), so stkbar may be
 		// inconsistent with the barriers on the stack.