From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail3-164.sinamail.sina.com.cn (mail3-164.sinamail.sina.com.cn [202.108.3.164]) (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 9AB9821322F for ; Sat, 29 Nov 2025 22:01:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.108.3.164 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764453681; cv=none; b=WYhbOqbfWm7UvQkQlUgMDIjFNp8uehqHhnNOFMbRnX0/jbDuPIsEoSIgR7OeBkUjurtelBAkC6Gl6z4h9Nne6VMmhALQf/SYUFLsa5aGjy52lxAFM4FTpg5n27Y7adnva443s6YcilC4etRZV2mjaaJAh25RLa0bWJag5c5wVEc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764453681; c=relaxed/simple; bh=Z5Ysi1nZthNoX3ZTj9X1cnhQ9qj2aRL5xrHHmqEMy7g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uNSF10dFGU4UNLKtye82MyO4jJPaio76z0UZpK5HnrBIzfv5i9katg3Q3xcATwE1CeMlmMeV622/OZfQDnB1frWz/28UsE0kNXo6HL+h2ksv4GfXZirIMdpxE9huMxwzHbbIYLzPlBwE4PJTatGQaR1gcyI6Pg3wHfh0ECS9Azo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b=QlMgKYBE; arc=none smtp.client-ip=202.108.3.164 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b="QlMgKYBE" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sina.com; s=201208; t=1764453675; bh=KHInF8H5mt4kBSYKV3nHLKj7hBokJ1lgGVlrnm69Fi0=; h=From:Subject:Date:Message-ID; b=QlMgKYBEqFRqF3+gCqkpIHpSbTMop4npKYWjFwlVcSrlcciRqASs0k6RJqTdb1JEh NdtWyvXeEdj6K5RwH7RlVCiLKtucCkOhYKEZrds1ucj4qvOVdgeV2/29q3NxkO6d3e gFKwkyeDXEPVE8doPPX7Ho/J8LzKn7ugM/KCYxMA= X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([114.249.57.85]) by sina.com (10.54.253.32) with ESMTP id 692B6C8E0000720D; Sat, 30 Nov 2025 05:58:42 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 4075114456637 X-SMAIL-UIID: F787940F611B42988416D35D5757D4AB-20251130-055842-1 From: Hillf Danton To: syzbot Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [overlayfs?] WARNING in fast_dput Date: Sun, 30 Nov 2025 05:58:27 +0800 Message-ID: <20251129215828.9544-1-hdanton@sina.com> In-Reply-To: <692aef93.a70a0220.d98e3.015b.GAE@google.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > Date: Sat, 29 Nov 2025 05:05:23 -0800 [thread overview] > Hello, > > syzbot found the following issue on: > > HEAD commit: 7d31f578f323 Add linux-next specific files for 20251128 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=14db5f42580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=6336d8e94a7c517d > dashboard link: https://syzkaller.appspot.com/bug?extid=b74150fd2ef40e716ca2 > compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1780a112580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10f6be92580000 #syz test --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -1224,9 +1224,9 @@ int ovl_lock_rename_workdir(struct dentr goto err; if (trap) goto err_unlock; - if (work && work->d_parent != workdir) + if (work && (work->d_parent != workdir || d_unhashed(work))) goto err_unlock; - if (upper && upper->d_parent != upperdir) + if (upper && (upper->d_parent != upperdir || d_unhashed(work))) goto err_unlock; return 0; --