From: Russ Cox <rsc@golang.org>
Date: Wed, 27 Jan 2016 04:00:41 +0000 (-0500)
Subject: runtime: guard against array out of bounds in GoroutineProfile
X-Git-Tag: go1.6rc1~20
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=d9fdbf48207e24c1d0d771250f2cc811ef97adff;p=gostls13.git

runtime: guard against array out of bounds in GoroutineProfile

The previous CL is the real fix. This one is just insurance.

Fixes #14046 again.

Change-Id: I553349504bb1789e4b66c888dbe4034568918ad6
Reviewed-on: https://go-review.googlesource.com/18977
Reviewed-by: Austin Clements <austin@google.com>
---

diff --git a/src/runtime/mprof.go b/src/runtime/mprof.go
index e45bc7a770..fc73bbfbe1 100644
--- a/src/runtime/mprof.go
+++ b/src/runtime/mprof.go
@@ -554,6 +554,11 @@ func GoroutineProfile(p []StackRecord) (n int, ok bool) {
 		// Save other goroutines.
 		for _, gp1 := range allgs {
 			if isOK(gp1) {
+				if len(r) == 0 {
+					// Should be impossible, but better to return a
+					// truncated profile than to crash the entire process.
+					break
+				}
 				saveg(^uintptr(0), ^uintptr(0), gp1, &r[0])
 				r = r[1:]
 			}