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 9F76C29A9C8 for ; Fri, 24 Oct 2025 09:05:11 +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=1761296715; cv=none; b=Yhg2p4Bu+VvUxF8l8amNRR7CoWey2ECptHMXMFKGTBeq/qQMWJDeGfR7n5PMfYD517f7wpc4uSSn2aRSnEfHW+B6L7nyOFk2HP0+f4uUmcu6LRZdjHt5rTeoVbkxtxYt7YYBhoBa75deE7qN57AhKZfvTX1zthK9IG1A/w3jVCU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761296715; c=relaxed/simple; bh=ymO0o4Ev+efZ6uTLHPMrvkJMyI81gAD46z5c6c4pKOw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=V4MJZOAuOGt0yR7pdLK8U/E3uk6PUYK2oY1JPqonOoNACqup/oYZryMH4T3dJnOSfHr0w7Rd/3nrBweIwBPcfCvwLX2B6kJnkg2TBv/A9X23s6SNx8nk+ji8HYzjRCZxGZcTV1z50y/dEAHFYr8sC0lUWwHn3+mTYVACbthiARY= 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=SoDYFXHL; 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="SoDYFXHL" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1761296709; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=vBS/sy8hIvdg6pdyqaf8XlsWh8LXpRJ1Obj39CR0eqg=; b=SoDYFXHLHvI6rDMVidBirls4NzkVbABTW0ECObmm4H7IrNswCE/1yl3roCRNNI6tJ5NFMY+AG0rfMeh7ipD7QHnd04I+f+cjIXwXDDN8A/sJqR7o7265ITlXxjnkD75b1y8b4YOO8lRZHJdEx1QjlTSZ135TS6UpGNl2igzu7jE= Received: from 30.221.128.124(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0Wqtt5Kc_1761296708 cluster:ay36) by smtp.aliyun-inc.com; Fri, 24 Oct 2025 17:05:09 +0800 Message-ID: Date: Fri, 24 Oct 2025 17:05:08 +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 v2] 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> <20251024023056.29275-2-eraykrdg1@gmail.com> From: Joseph Qi In-Reply-To: <20251024023056.29275-2-eraykrdg1@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2025/10/24 10:30, 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. > --- > v2: > - Reviewed how ext4 handling same situation and we come up with this > solution > --- The version change log should be after your SOB. > 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 > --- > fs/ocfs2/inode.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c > index 14bf440ea4df..6c936f62b169 100644 > --- a/fs/ocfs2/inode.c > +++ b/fs/ocfs2/inode.c > @@ -1455,7 +1455,15 @@ int ocfs2_validate_inode_block(struct super_block *sb, > (unsigned long long)bh->b_blocknr); > goto bail; > } > - > + if (di->i_links_count == 0) { > + if (le16_to_cpu(di->i_mode) == 0 || > + !(le32_to_cpu(di->i_flags) & OCFS2_ORPHANED_FL)) { Why not put those in a single check? BTW, i_links_count is little endian and should convert to host endian first. And we'd prefer the following alignment: if (!le16_to_cpu(di->i_links_count) && !le16_to_cpu(di->i_mode) && !(le32_to_cpu(di->i_flags) & OCFS2_ORPHANED_FL)) ...... Thanks, Joseph > + mlog(ML_ERROR, "Invalid dinode #%llu: i_mode is zero!\n", > + (unsigned long long)bh->b_blocknr); > + rc = -EFSCORRUPTED; > + goto bail; > + } > + } > /* > * Errors after here are fatal. > */