From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 52E5C200112; Tue, 26 Aug 2025 11:47:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756208866; cv=none; b=JxYIRXRRFmRKw/nn/ZboJ8+EGvQYgn22Nne9aBrmH7ZzjW11jke3JF3bveCBvzdflwhw3W+0mTny1D8PLnKtNaI3HbOmlWZOGvbXnfQ5Uaq8QUfMUfkuij02j+cIndhcoS7mlg379sh/SWhmHLaw62ckchon33hEL9BXNFzTiGg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756208866; c=relaxed/simple; bh=0WzY9JyZJGgTYconLoP2mrOX5LE83s6AyZNeyrBwk6w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=I3LPAUYHP8AA9twez6od0+ZOUry8g6ku9NCaMzGy9h4KtfMr4wKmXaD58bhy7ydvOOR/HrAH9Pod2MTshKi4hau4jbNyl470iND6HEXEKVBedXe1mUQfSrXEseF6cefAz1ADbT4D3QCVLidPnEiytNbfp3X1F+XOxFpuImeihtY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=YmWIpD+m; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="YmWIpD+m" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D7799C4CEF1; Tue, 26 Aug 2025 11:47:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756208866; bh=0WzY9JyZJGgTYconLoP2mrOX5LE83s6AyZNeyrBwk6w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YmWIpD+mKQF2RNg/KR39xEXd1BysWqNQbsFpMZRSyvGvKpYPxvFjZmxh+0lgdlQS5 0CJO2y2pMkkDsw+vKDoXZfyeBGx1c0NN4RWAXR1ZaMXL/k8Q0CA7n2g2phD/MrMUO2 pbD2JhncDMJQBoGDL5cH/6y7lJEVciKrxkemjWRs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+7836a68852a10ec3d790@syzkaller.appspotmail.com, NeilBrown , Amir Goldstein Subject: [PATCH 6.12 244/322] ovl: use I_MUTEX_PARENT when locking parent in ovl_create_temp() Date: Tue, 26 Aug 2025 13:10:59 +0200 Message-ID: <20250826110921.946488358@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110915.169062587@linuxfoundation.org> References: <20250826110915.169062587@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown commit 5f1c8965e748c150d580a2ea8fbee1bd80d07a24 upstream. ovl_create_temp() treats "workdir" as a parent in which it creates an object so it should use I_MUTEX_PARENT. Prior to the commit identified below the lock was taken by the caller which sometimes used I_MUTEX_PARENT and sometimes used I_MUTEX_NORMAL. The use of I_MUTEX_NORMAL was incorrect but unfortunately copied into ovl_create_temp(). Note to backporters: This patch only applies after the last Fixes given below (post v6.16). To fix the bug in v6.7 and later the inode_lock() call in ovl_copy_up_workdir() needs to nest using I_MUTEX_PARENT. Link: https://lore.kernel.org/all/67a72070.050a0220.3d72c.0022.GAE@google.com/ Cc: stable@vger.kernel.org Reported-by: syzbot+7836a68852a10ec3d790@syzkaller.appspotmail.com Tested-by: syzbot+7836a68852a10ec3d790@syzkaller.appspotmail.com Fixes: c63e56a4a652 ("ovl: do not open/llseek lower file with upper sb_writers held") Fixes: d2c995581c7c ("ovl: Call ovl_create_temp() without lock held.") Signed-off-by: NeilBrown Signed-off-by: Amir Goldstein Signed-off-by: Greg Kroah-Hartman --- fs/overlayfs/copy_up.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -780,7 +780,7 @@ static int ovl_copy_up_workdir(struct ov return err; ovl_start_write(c->dentry); - inode_lock(wdir); + inode_lock_nested(wdir, I_MUTEX_PARENT); temp = ovl_create_temp(ofs, c->workdir, &cattr); inode_unlock(wdir); ovl_end_write(c->dentry);