From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-112.freemail.mail.aliyun.com (out30-112.freemail.mail.aliyun.com [115.124.30.112]) (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 6E852155C97 for ; Wed, 3 Dec 2025 01:04:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.112 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764723866; cv=none; b=NMW/LYAKFLZmlnBm/fsU8tnZ8KH8s8w2hzKUIrU7rzYXW3bE2c0cujSmJAx4nXVkiGKoWpoBAsCrPBLxRnVfVpQu4Xg9p6zJp1m5qF6OivNy6tBY8GP30pTkAF6fjntUOE2fC72z1b03bPJKReOAhlCM7otTF2/VDpI3CHKJtyI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764723866; c=relaxed/simple; bh=F5uSWUvnACQXUIpvYdZl8rUAm1cPYBlzjzqgIVKhfR0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ge5DUbeI4OgdDvP8WngfFc3tATTe6e32cRS6jlaPmkUu2M72owzK3biDf4oytNVy5Z/jRm3hEkfNCpjANJXJZBhm6q8GZDZi8+R8IepQtnmetf4z/ILhu51ZXhPGnU6dyOYV4DxqLXaGiZCB5HIQQWBspq54EPZ4KHnlhucJY/M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=s6h2QGRo; arc=none smtp.client-ip=115.124.30.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="s6h2QGRo" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1764723855; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=6ES2tsQbOs6cUaAl9oROxPHl0Mr/J/TwFpPvl9Hl+/8=; b=s6h2QGRouVfohxm5EPWu/p8lZ6lGH4vUa7JjuF4e+Qhe8goGkpUiCRi99jJQk01zbkQ79QMzWLzqvlaS9R+Ubc5ICBrD3PpUAjkWZrnvjiqLtMTJpDt/KZ7VZaEwne5i38DBGBaOqmmKibyR73M/anV0lnIGqV9WK7mSklQtVDw= Received: from 30.221.128.156(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0Wtyn.3V_1764723853 cluster:ay36) by smtp.aliyun-inc.com; Wed, 03 Dec 2025 09:04:14 +0800 Message-ID: Date: Wed, 3 Dec 2025 09:04:13 +0800 Precedence: bulk X-Mailing-List: ocfs2-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6] ocfs2: Invalidate inode if i_mode is zero after block read To: Ahmet Eray Karadag , mark@fasheh.com, jlbec@evilplan.org, akpm Cc: ocfs2-devel@lists.linux.dev, linux-kernel@vger.kernel.org, david.hunter.linux@gmail.com, skhan@linuxfoundation.org, syzbot+55c40ae8a0e5f3659f2b@syzkaller.appspotmail.com, Albin Babu Varghese References: <20251108120133.37443-3-eraykrdg1@gmail.com> <20251202224507.53452-2-eraykrdg1@gmail.com> From: Joseph Qi In-Reply-To: <20251202224507.53452-2-eraykrdg1@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2025/12/3 06:45, Ahmet Eray Karadag wrote: > A panic occurs in ocfs2_unlink due to WARN_ON(inode->i_nlink == 0) when > handling a corrupted inode with i_mode=0 and i_nlink=0 in memory. > > This "zombie" inode is created because ocfs2_read_locked_inode proceeds > even after ocfs2_validate_inode_block successfully validates a block > that structurally looks okay (passes checksum, signature etc.) but > contains semantically invalid data (specifically i_mode=0). The current > validation function doesn't check for i_mode being zero. > > This results in an in-memory inode with i_mode=0 being added to the VFS > cache, which later triggers the panic during unlink. > > Prevent this by adding an explicit check for (i_mode == 0, i_nlink == 0, non-orphan) > within ocfs2_validate_inode_block. If the check is true, return -EFSCORRUPTED to signal > corruption. This causes the caller (ocfs2_read_locked_inode) to invoke > make_bad_inode(), correctly preventing the zombie inode from entering > the cache. > > Reported-by: syzbot+55c40ae8a0e5f3659f2b@syzkaller.appspotmail.com > Fixes: https://syzkaller.appspot.com/bug?extid=55c40ae8a0e5f3659f2b > Co-developed-by: Albin Babu Varghese > Signed-off-by: Albin Babu Varghese > Signed-off-by: Ahmet Eray Karadag Reviewed-by: Joseph Qi > Previous link: https://lore.kernel.org/all/20251022222752.46758-2-eraykrdg1@gmail.com/T/ > --- > v2: > - Only checking either i_links_count == 0 or i_mode == 0 > - Not performing le16_to_cpu() anymore > - Tested with ocfs2-test > --- > v3: > - Add checking both high and low bits of i_links_count > --- > v4: > - Reading i_links_count hi and low bits without helper function > to save few cpu cycles > --- > v5: > - Clear i_links_count check > - Log the actual i_nlink/i_mode > --- > v6: > - Use `ocfs2_read_links_count` to get nlink > - Convert di->imode to cpu endian > --- > fs/ocfs2/inode.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c > index 14bf440ea4df..f83b8e4f4d8b 100644 > --- a/fs/ocfs2/inode.c > +++ b/fs/ocfs2/inode.c > @@ -1456,6 +1456,14 @@ int ocfs2_validate_inode_block(struct super_block *sb, > goto bail; > } > > + if ((!di->i_links_count && !di->i_links_count_hi) || !di->i_mode) { > + mlog(ML_ERROR, "Invalid dinode #%llu: " > + "Corrupt state (nlink = %u or mode = %u) detected!\n", > + (unsigned long long)bh->b_blocknr, > + ocfs2_read_links_count(di), le16_to_cpu(di->i_mode)); > + rc = -EFSCORRUPTED; > + goto bail; > + } > /* > * Errors after here are fatal. > */