From 5f9bd8a53b208bad3fe3e5cace82c4521dc9c2b3 Mon Sep 17 00:00:00 2001
From: Rahat Mahmood <rahat@google.com>
Date: Mon, 18 Apr 2022 17:25:50 -0700
Subject: [PATCH] cgroupfs: Synchronize access to cpuset controller bitmaps.

Reported-by: syzbot+98719e57f6acbe602b7f@syzkaller.appspotmail.com
PiperOrigin-RevId: 442672867
---
 pkg/sentry/fsimpl/cgroupfs/cpuset.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pkg/sentry/fsimpl/cgroupfs/cpuset.go b/pkg/sentry/fsimpl/cgroupfs/cpuset.go
index 8307d15a8..9f938306c 100644
--- a/pkg/sentry/fsimpl/cgroupfs/cpuset.go
+++ b/pkg/sentry/fsimpl/cgroupfs/cpuset.go
@@ -65,6 +65,8 @@ func newCPUSetController(k *kernel.Kernel, fs *filesystem) *cpusetController {
 
 // Clone implements controller.Clone.
 func (c *cpusetController) Clone() controller {
+	c.mu.Lock()
+	defer c.mu.Unlock()
 	cpus := c.cpus.Clone()
 	mems := c.mems.Clone()
 	new := &cpusetController{