From: Michael Anthony Knyszek <mknyszek@google.com>
Date: Tue, 26 Nov 2019 21:16:43 +0000 (+0000)
Subject: runtime: reset scavenge address in scavengeAll
X-Git-Tag: go1.14beta1~91
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=4e3d58009a1ba08e41dd1ec33691120a76a06af9;p=gostls13.git

runtime: reset scavenge address in scavengeAll

Currently scavengeAll (which is called by debug.FreeOSMemory) doesn't
reset the scavenge address before scavenging, meaning it could miss
large portions of the heap. Fix this by reseting the address before
scavenging, which will ensure it is able to walk over the entire heap.

Fixes #35858.

Change-Id: I4a7408050b8e134318ff94428f98cb96a1795aa9
Reviewed-on: https://go-review.googlesource.com/c/go/+/208960
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
---

diff --git a/src/runtime/mheap.go b/src/runtime/mheap.go
index 3f3e36728b..114c97b874 100644
--- a/src/runtime/mheap.go
+++ b/src/runtime/mheap.go
@@ -1424,6 +1424,8 @@ func (h *mheap) scavengeAll() {
 	gp := getg()
 	gp.m.mallocing++
 	lock(&h.lock)
+	// Reset the scavenger address so we have access to the whole heap.
+	h.pages.resetScavengeAddr()
 	released := h.pages.scavenge(^uintptr(0), true)
 	unlock(&h.lock)
 	gp.m.mallocing--