From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com [115.124.30.132]) (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 018632FD7CA for ; Tue, 2 Dec 2025 06:17:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.132 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764656232; cv=none; b=gGcRWI9p1XTQBWugDxuXuUrmCecHyjGJmeA58gq3XtE1weHTWw7SdD255ePRxSOfDiSYwyXD0cGQpT0Q84OV3NiOZeL0eJLqGK+XdCXgY+F3LHMYAyCnXdnBY0Tgt3phMWPFQcv9v81ZUM7JvIFya4FBxivOIQ31zt+77Oabugo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764656232; c=relaxed/simple; bh=yb6ZM8y6BeOOBjacvLvS46rC1H0Qv1yJ5bga74I58Qg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=t7cFn3UlS6In0MmJQcHWp28de4qIySps54AbKGh22njlTxmPPw1/dSndxIZeQB25k5KIHuNKGHDKt/TavggS4+f+CRQtc8YmnufrbykoR4pmrZuC5UVoSjs2UQS6rnQENBp2tBuX2dZ4x0Hbr5yQFJW7RsAe4cbwuhLi3P9kDBw= 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=iswtzwpR; arc=none smtp.client-ip=115.124.30.132 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="iswtzwpR" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1764656217; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=IiLWJ4yqEBxjoNEx6cYypR+Pdv1UUnacaVj+NmacKag=; b=iswtzwpRChHdqm4QCVLCDqfQuRVX+vfpQyXbIJ6FCfVq5j8iLWIlXPAmB+qzxVBO0AZhBaLGXJsmjJV0o8z8dfECVcqa0rN36nQnKS4CmxcAGolQQ88yDSHwK/CX0KB5jUCU4egMeu+vET+EqVQSWUgpACfKFAEHqxiY/CAbKLY= Received: from 30.221.128.146(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0WtvIFND_1764656216 cluster:ay36) by smtp.aliyun-inc.com; Tue, 02 Dec 2025 14:16:56 +0800 Message-ID: <8ede6a79-adb8-4b89-a8c2-d0cf57ff2267@linux.alibaba.com> Date: Tue, 2 Dec 2025 14:16:55 +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 v5] ocfs2: Invalidate inode if i_mode is zero after block read To: Heming Zhao , Ahmet Eray Karadag Cc: mark@fasheh.com, jlbec@evilplan.org, 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> <20251202035213.633096-2-eraykrdg1@gmail.com> From: Joseph Qi In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2025/12/2 14:15, Heming Zhao wrote: > On Tue, Dec 02, 2025 at 06:52:14AM +0300, 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 >> --- >> v5: >> - Clear i_links_count check >> - Log the actual i_nlink/i_mode >> --- >> fs/ocfs2/inode.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c >> index 14bf440ea4df..08ce0846289c 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, >> + (di->i_links_count_hi | di->i_links_count), di->i_mode); > > The '|' logic is meaningless here. Because the error case is rare, you can simply > call ocfs2_read_links_count(di). > Yes, also 'di->i_mode' should be converted to cpu endian as well. Joseph