From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-118.freemail.mail.aliyun.com (out30-118.freemail.mail.aliyun.com [115.124.30.118]) (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 4479718BC3D for ; Tue, 2 Dec 2025 02:44:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.118 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764643469; cv=none; b=AhP1YyXj7A/n7ceuJIyNK4tXzMk3yTQ0rfnYMj1Jta5CPISE9FJ4ydJisV1XHQvHuB4CVY6xjeJE0HAqkRlJe1YWW8qFuqewrOftGENIASSIhESD2+Lh43r6O30VSMqKks9Jd3Y4MACyo1nIgTI1uBXK8O7EmuzEchKZ4EN21zk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764643469; c=relaxed/simple; bh=Y+lDkBQKhf8AcqA6IB6fRXOkcTDphlTFH3shFbcemOg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Re1KgYxaPCI0Aw/bOWC0YOnawFhjGs54TYB319kaQQlK4y8t6eXtZmJflPaOu7YFh8lfPcfZKRcy8uwNOy4tOoC5vr/GvKV8JHTzWJYEOyxBZHJzzJX0BWgSggCVWkhm7Qsd6HECBgH4+rA7l/JaBYh21pj3hstaYJjM9x0+X4g= 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=m1dqznwu; arc=none smtp.client-ip=115.124.30.118 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="m1dqznwu" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1764643463; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=tm/FdjxSd9aF1a1xENueqL6aA+v+Zrvjbdq0I6wLjzA=; b=m1dqznwuAj/qeQh+e3NLM4Y9f7tUUBL41HBpy2a5eU/5yBSKdIC0j34zWxvrQGIenq5I7mE6asms1argf2fp1txhaqSAET/ldgMg3U24VRbv2pjF2NFE3cJQ6pEhylsPX24J82GU8uux87FCl7VHNUYmw66YpYOCzt3KOcsN+Uc= Received: from 30.221.128.146(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0WtuWmZc_1764643461 cluster:ay36) by smtp.aliyun-inc.com; Tue, 02 Dec 2025 10:44:22 +0800 Message-ID: <5d9b1739-2337-41ad-8c92-38828c8f5c32@linux.alibaba.com> Date: Tue, 2 Dec 2025 10:44:21 +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 v4] ocfs2: Invalidate inode if i_mode is zero after block read To: Ahmet Eray Karadag , mark@fasheh.com, jlbec@evilplan.org, Heming Zhao 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> <20251202003209.188987-2-eraykrdg1@gmail.com> From: Joseph Qi In-Reply-To: <20251202003209.188987-2-eraykrdg1@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2025/12/2 08:32, 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 > 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 > --- > fs/ocfs2/inode.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c > index 14bf440ea4df..34c2882273ae 100644 > --- a/fs/ocfs2/inode.c > +++ b/fs/ocfs2/inode.c > @@ -1455,7 +1455,13 @@ int ocfs2_validate_inode_block(struct super_block *sb, > (unsigned long long)bh->b_blocknr); > goto bail; > } > - > + if (!(di->i_links_count | di->i_links_count_hi) || !di->i_mode) { "(di->i_links_count | di->i_links_count_hi)" looks meaningless. So if we don't want to introduce the endian coversion here, how about: if ((!di->i_links_count && !di->i_links_count_hi) || !di->i_mode) { ... } Heming, what's your opinion? > + mlog(ML_ERROR, "Invalid dinode #%llu: " > + "Corrupt state (nlink=0 or mode=0,) detected!\n", Better to log the actual i_nlink/i_mode. e.g. "corrupted i_nlink %u or i_mode %u\n" ... Joseph > + (unsigned long long)bh->b_blocknr); > + rc = -EFSCORRUPTED; > + goto bail; > + } > /* > * Errors after here are fatal. > */