diff --git a/misc/cgo/testplugin/altpath/src/common/common.go b/misc/cgo/testplugin/altpath/src/common/common.go
new file mode 100644
index 00000000000..505ba02b1f1
--- /dev/null
+++ b/misc/cgo/testplugin/altpath/src/common/common.go
@@ -0,0 +1,11 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package common
+
+var X int
+
+func init() {
+	X = 4
+}
diff --git a/misc/cgo/testplugin/altpath/src/plugin-mismatch/main.go b/misc/cgo/testplugin/altpath/src/plugin-mismatch/main.go
new file mode 100644
index 00000000000..8aacafc4530
--- /dev/null
+++ b/misc/cgo/testplugin/altpath/src/plugin-mismatch/main.go
@@ -0,0 +1,17 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+// // No C code required.
+import "C"
+
+// The common package imported here does not match the common package
+// imported by plugin1. A program that attempts to load plugin1 and
+// plugin-mismatch should produce an error.
+import "common"
+
+func ReadCommonX() int {
+	return common.X
+}
diff --git a/misc/cgo/testplugin/src/host/host.go b/misc/cgo/testplugin/src/host/host.go
index 477a9e63a28..b3b4df3d584 100644
--- a/misc/cgo/testplugin/src/host/host.go
+++ b/misc/cgo/testplugin/src/host/host.go
@@ -9,6 +9,7 @@ import (
 	"log"
 	"path/filepath"
 	"plugin"
+	"strings"
 
 	"common"
 )
@@ -104,5 +105,13 @@ func main() {
 		log.Fatalf("after loading plugin2, common.X=%d, want %d", got, want)
 	}
 
+	_, err = plugin.Open("plugin-mismatch.so")
+	if err == nil {
+		log.Fatal(`plugin.Open("plugin-mismatch.so"): should have failed`)
+	}
+	if s := err.Error(); !strings.Contains(s, "different version") {
+		log.Fatalf(`plugin.Open("plugin-mismatch.so"): error does not mention "different version": %v`, s)
+	}
+
 	fmt.Println("PASS")
 }
diff --git a/misc/cgo/testplugin/test.bash b/misc/cgo/testplugin/test.bash
index 322d43901da..bba46b51c66 100755
--- a/misc/cgo/testplugin/test.bash
+++ b/misc/cgo/testplugin/test.bash
@@ -24,6 +24,7 @@ mkdir sub
 
 GOPATH=$(pwd) go build -buildmode=plugin plugin1
 GOPATH=$(pwd) go build -buildmode=plugin plugin2
+GOPATH=$(pwd)/altpath go build -buildmode=plugin plugin-mismatch
 GOPATH=$(pwd) go build -buildmode=plugin -o=sub/plugin1.so sub/plugin1
 GOPATH=$(pwd) go build host
 
diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index 8c2d31c8412..e4c34750c77 100644
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -720,7 +720,7 @@ func objfile(ctxt *Link, lib *Library) {
 		goto out
 	}
 
-	if Buildmode == BuildmodeShared {
+	if Buildmode == BuildmodeShared || Buildmode == BuildmodePlugin || ctxt.Syms.ROLookup("plugin.Open", 0) != nil {
 		before := f.Offset()
 		pkgdefBytes := make([]byte, atolwhex(arhdr.size))
 		if _, err := io.ReadFull(f, pkgdefBytes); err != nil {
diff --git a/src/cmd/link/internal/ld/symtab.go b/src/cmd/link/internal/ld/symtab.go
index 323136c6f91..98ce3ad79b8 100644
--- a/src/cmd/link/internal/ld/symtab.go
+++ b/src/cmd/link/internal/ld/symtab.go
@@ -530,6 +530,20 @@ func (ctxt *Link) symtab() {
 		Addaddr(ctxt, abihashgostr, hashsym)
 		adduint(ctxt, abihashgostr, uint64(hashsym.Size))
 	}
+	if Buildmode == BuildmodePlugin || ctxt.Syms.ROLookup("plugin.Open", 0) != nil {
+		for _, l := range ctxt.Library {
+			s := ctxt.Syms.Lookup("go.link.pkghashbytes."+l.Pkg, 0)
+			s.Attr |= AttrReachable
+			s.Type = obj.SRODATA
+			s.Size = int64(len(l.hash))
+			s.P = []byte(l.hash)
+			str := ctxt.Syms.Lookup("go.link.pkghash."+l.Pkg, 0)
+			str.Attr |= AttrReachable
+			str.Type = obj.SRODATA
+			Addaddr(ctxt, str, s)
+			adduint(ctxt, str, uint64(len(l.hash)))
+		}
+	}
 
 	nsections := textsectionmap(ctxt)
 
@@ -604,7 +618,28 @@ func (ctxt *Link) symtab() {
 	}
 	if Buildmode == BuildmodePlugin {
 		addgostring(ctxt, moduledata, "go.link.thispluginpath", *flagPluginPath)
+
+		pkghashes := ctxt.Syms.Lookup("go.link.pkghashes", 0)
+		pkghashes.Attr |= AttrReachable
+		pkghashes.Attr |= AttrLocal
+		pkghashes.Type = obj.SRODATA
+
+		for i, l := range ctxt.Library {
+			// pkghashes[i].name
+			addgostring(ctxt, pkghashes, fmt.Sprintf("go.link.pkgname.%d", i), l.Pkg)
+			// pkghashes[i].linktimehash
+			addgostring(ctxt, pkghashes, fmt.Sprintf("go.link.pkglinkhash.%d", i), string(l.hash))
+			// pkghashes[i].runtimehash
+			hash := ctxt.Syms.ROLookup("go.link.pkghash."+l.Pkg, 0)
+			Addaddr(ctxt, pkghashes, hash)
+		}
+		Addaddr(ctxt, moduledata, pkghashes)
+		adduint(ctxt, moduledata, uint64(len(ctxt.Library)))
+		adduint(ctxt, moduledata, uint64(len(ctxt.Library)))
 	} else {
+		adduint(ctxt, moduledata, 0) // pluginpath
+		adduint(ctxt, moduledata, 0)
+		adduint(ctxt, moduledata, 0) // pkghashes slice
 		adduint(ctxt, moduledata, 0)
 		adduint(ctxt, moduledata, 0)
 	}
diff --git a/src/plugin/plugin_dlopen.go b/src/plugin/plugin_dlopen.go
index f4addde74ce..c5b0a4721c5 100644
--- a/src/plugin/plugin_dlopen.go
+++ b/src/plugin/plugin_dlopen.go
@@ -69,7 +69,11 @@ func open(name string) (*Plugin, error) {
 		name = name[:len(name)-3]
 	}
 
-	pluginpath, syms := lastmoduleinit()
+	pluginpath, syms, mismatchpkg := lastmoduleinit()
+	if mismatchpkg != "" {
+		pluginsMu.Unlock()
+		return nil, errors.New("plugin.Open: plugin was built with a different version of package " + mismatchpkg)
+	}
 	if plugins == nil {
 		plugins = make(map[string]*Plugin)
 	}
@@ -131,4 +135,4 @@ var (
 )
 
 // lastmoduleinit is defined in package runtime
-func lastmoduleinit() (pluginpath string, syms map[string]interface{})
+func lastmoduleinit() (pluginpath string, syms map[string]interface{}, mismatchpkg string)
diff --git a/src/runtime/plugin.go b/src/runtime/plugin.go
index 7907936e144..845bf76e92c 100644
--- a/src/runtime/plugin.go
+++ b/src/runtime/plugin.go
@@ -7,7 +7,7 @@ package runtime
 import "unsafe"
 
 //go:linkname plugin_lastmoduleinit plugin.lastmoduleinit
-func plugin_lastmoduleinit() (path string, syms map[string]interface{}) {
+func plugin_lastmoduleinit() (path string, syms map[string]interface{}, mismatchpkg string) {
 	md := firstmoduledata.next
 	if md == nil {
 		throw("runtime: no plugin module data")
@@ -41,6 +41,11 @@ func plugin_lastmoduleinit() (path string, syms map[string]interface{}) {
 			throw("plugin: new module data overlaps with previous moduledata")
 		}
 	}
+	for _, pkghash := range md.pkghashes {
+		if pkghash.linktimehash != *pkghash.runtimehash {
+			return "", nil, pkghash.modulename
+		}
+	}
 
 	// Initialize the freshly loaded module.
 	modulesinit()
@@ -74,7 +79,7 @@ func plugin_lastmoduleinit() (path string, syms map[string]interface{}) {
 		}
 		syms[name] = val
 	}
-	return md.pluginpath, syms
+	return md.pluginpath, syms, ""
 }
 
 // inRange reports whether v0 or v1 are in the range [r0, r1].
diff --git a/src/runtime/symtab.go b/src/runtime/symtab.go
index bba3ccfc206..686af08ef03 100644
--- a/src/runtime/symtab.go
+++ b/src/runtime/symtab.go
@@ -202,7 +202,9 @@ type moduledata struct {
 
 	ptab []ptabEntry
 
-	pluginpath   string
+	pluginpath string
+	pkghashes  []modulehash
+
 	modulename   string
 	modulehashes []modulehash
 
@@ -213,10 +215,18 @@ type moduledata struct {
 	next *moduledata
 }
 
+// A modulehash is used to compare the ABI of a new module or a
+// package in a new module with the loaded program.
+//
 // For each shared library a module links against, the linker creates an entry in the
 // moduledata.modulehashes slice containing the name of the module, the abi hash seen
 // at link time and a pointer to the runtime abi hash. These are checked in
 // moduledataverify1 below.
+//
+// For each loaded plugin, the the pkghashes slice has a modulehash of the
+// newly loaded package that can be used to check the plugin's version of
+// a package against any previously loaded version of the package.
+// This is done in plugin.lastmoduleinit.
 type modulehash struct {
 	modulename   string
 	linktimehash string