From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-98.freemail.mail.aliyun.com (out30-98.freemail.mail.aliyun.com [115.124.30.98]) (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 B62C81DE2A7 for ; Sat, 25 Oct 2025 12:24:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.98 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761395081; cv=none; b=lUa0yCYt2m/tzv0XTAeLaiSG3eBLBhnNNwEiE6ya7T6JMwTQO1eqY4gKwhocxcDvW2GprSGocGqmBA80SmorXoh2QjPYQCv0P/DVJpFhMjQlltluPI9zDbJfqWlcAakpvsXvFy/ETcA7W1UmWDs27IsJq0tCN+rTrZGmXRR9Xc8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761395081; c=relaxed/simple; bh=2583AJYDJNkBUrFMwfw3UO/9QBRLf7JT7gJQRZKA7lM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Yx5VPInIZo/6CJ3hOLS7x9LwhMA+0aUEztCNHq7K0NakzWPh3LXxuBmHp2WitSQAUwaS2FGxttIG0/j+3blNMQYZkg0EhqjI9u8/G+uNYU5U9rwzLrGJ2HGnlumzTL/3aKfNYDkNQj0wlft8u89bnvO1vlNiwmrRWZzBxRhJkmk= 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=gQuJROW8; arc=none smtp.client-ip=115.124.30.98 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="gQuJROW8" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1761395070; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=QBkOSh4GSFWfzEtwF628TabusJ5AWIKyvv1Mv/HXDb4=; b=gQuJROW8UCjql5Iaejtx75jDRtG0a0HCaX3+13GuIfGkM8ZEiPhMqpdf7VNIakbe7FYAVF27PEvO+avaSbCGxcLtqqDME/O3K8IZ8GYtwo0S8bFOkY12B2JuK+Y9D9ubcNZFiVAlpFjnYRG76fv6VgiEPfwl9RzHigtCaWbu9c0= Received: from 30.41.143.132(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0Wqwtpv1_1761395069 cluster:ay36) by smtp.aliyun-inc.com; Sat, 25 Oct 2025 20:24:30 +0800 Message-ID: <192fd326-2963-4839-8a4b-79abfc4ad3bd@linux.alibaba.com> Date: Sat, 25 Oct 2025 20:24:29 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] ocfs2: Invalidate inode if i_mode is zero after block read To: Ahmet Eray Karadag , mark@fasheh.com, jlbec@evilplan.org 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: <20251022222752.46758-2-eraykrdg1@gmail.com> <20251025111355.32045-2-eraykrdg1@gmail.com> From: Joseph Qi In-Reply-To: <20251025111355.32045-2-eraykrdg1@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2025/10/25 19:13, 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 within > ocfs2_validate_inode_block. If i_mode is zero, 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. > > --- > [RFC]: > The current fix handles i_mode=0 corruption detected during inode read > by returning -EFSCORRUPTED from ocfs2_validate_inode_block, which leads to > make_bad_inode() being called, preventing the corrupted inode from > entering the cache. This approach avoids immediately forcing the entire > filesystem read-only, assuming the corruption might be localized to > this inode. > > Is this less aggressive error handling strategy appropriate for i_mode=0 > corruption? Or is this condition considered severe enough that we *should* > explicitly call ocfs2_error() within the validation function to guarantee > the filesystem is marked read-only immediately upon detection? > Feedback and testing on the correct severity assessment and error > handling for this type of corruption would be appreciated. > > 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 > --- > v2: > - Reviewed how ext4 handling same situation and we come up with this > solution > --- > v3: > - Implement combined check for nlink=0, mode=0 and non-orphan > as requested. > --- > fs/ocfs2/inode.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c > index 14bf440ea4df..3feeaa475b62 100644 > --- a/fs/ocfs2/inode.c > +++ b/fs/ocfs2/inode.c > @@ -1455,7 +1455,14 @@ int ocfs2_validate_inode_block(struct super_block *sb, > (unsigned long long)bh->b_blocknr); > goto bail; > } > - > + if (!le16_to_cpu(di->i_links_count) && !le16_to_cpu(di->i_mode) && > + !(le32_to_cpu(di->i_flags) & OCFS2_ORPHANED_FL)) { ^Better to align here. > + mlog(ML_ERROR, "Invalid dinode #%llu: " One tab is engough. Joseph > + "Corrupt state (nlink=0, mode=0, !orphan) detected!\n", > + (unsigned long long)bh->b_blocknr); > + rc = -EFSCORRUPTED; > + goto bail; > + } > /* > * Errors after here are fatal. > */