From 6448dbe1b7995949db8c83ffe5178e1747b549e1 Mon Sep 17 00:00:00 2001
From: Andrei Vagin <avagin@google.com>
Date: Thu, 18 Sep 2025 15:20:35 -0700
Subject: [PATCH] procfs: release the file system mutex on the error path

Reported-by: syzbot+7b4d0fefa2463e53c401@syzkaller.appspotmail.com
PiperOrigin-RevId: 808759083
---
 pkg/sentry/fsimpl/kernfs/filesystem.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pkg/sentry/fsimpl/kernfs/filesystem.go b/pkg/sentry/fsimpl/kernfs/filesystem.go
index e34d5ea284..6945b4b804 100644
--- a/pkg/sentry/fsimpl/kernfs/filesystem.go
+++ b/pkg/sentry/fsimpl/kernfs/filesystem.go
@@ -530,6 +530,7 @@ func (fs *Filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf
 		}
 		if trunc && d.isRegular() {
 			if err := mnt.CheckBeginWrite(); err != nil {
+				fs.mu.RUnlock()
 				return nil, err
 			}
 			defer mnt.EndWrite()