From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.manguebit.org (mx1.manguebit.org [143.255.12.172]) (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 993F6364931 for ; Wed, 30 Sep 2026 17:56:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=143.255.12.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790790992; cv=none; b=stslUNkXD5f/D0UBR4dInp6tHGTwlu3GEt+OQaiKPXTDW0Sb+EApZf1kGEBmEg9cWB3JO+kwJJ+AaZKT4LvFpRCq+No0+IxUI6MgfR+Bt2h6BkbOalploogVSUNLXpvl6SoZGlqWJ9rncjuWsQuXack9zbnSamsPC8kf6gpmZiY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790790992; c=relaxed/simple; bh=KS4QDGG3Uq4c1qv4hF+a3vEzQ4M7Ljnp/hKL5Il5CDE=; h=Message-ID:From:To:Cc:Subject:In-Reply-To:References:Date: MIME-Version:Content-Type; b=TzipLW+L0wZkDPLi8oyn+pbc65mJeBJsc0rxGC40SRBl02Q4aImQVNJvPnz4o3lReasNGlQakWhtK2GdLC0P/0O4UI3oqkPGHqF6ie/WsV3VfcUBi/5KgEUewZknUurKgolQTtMp92YVsVSIKJBpynHwdqz6vTims6v3X+o6NF8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=manguebit.org; spf=pass smtp.mailfrom=manguebit.org; dkim=pass (2048-bit key) header.d=manguebit.org header.i=@manguebit.org header.b=wToBainF; arc=none smtp.client-ip=143.255.12.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=manguebit.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=manguebit.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=manguebit.org header.i=@manguebit.org header.b="wToBainF" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=manguebit.org; s=dkim; h=Content-Type:MIME-Version:Date:References: In-Reply-To:Subject:Cc:To:From:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=euj7UTZXQdokpbSLplQ/LcnVUy9KnYpkW3sLYv1MiMU=; b=wToBainFHGlg7wr+17aFKv3qNB lpW1+B2CQ8HdXV8PoNMqFPVpkgRBWtjyTFVfp5NfpXvss9EJHpygAoCqTvdux6zgAh55rZfIV0CAg PKNiu+SaQVFpXD85s8TMs+TRlzHZls167QDY1EscZ9rJYKzp0p3HOTJ5qzp+2320rJR1ZDdwnNQM4 6b633NA/AgiXZ1MKQ25TP3ZNns53kgae7F6bVUSVBb76TkoK9p3A1uP36GPQ+ZSx7zw9GmmgTlY/F nXr/w4kfEyhfnrqYEUxMBjyfwwd/q/P8CfAxv5olp8LNvA8taWSeDseRnVWgJx8qino+hcjTB8WHD GsF0jh+A==; Received: from pc by mx1.manguebit.org with local (Exim 4.99.5) id 1xByXc-00000002e99-1KfF; Wed, 30 Sep 2026 14:56:28 -0300 Message-ID: From: Paulo Alcantara To: sorenson@redhat.com, CIFS Cc: Namjae Jeon , Henrique Carvalho Subject: Re: [Discuss] smb: client: bitfield aliasing and locking chaos in cifsFileInfo In-Reply-To: <7689764e-c0f6-4016-9557-b54cf4a3de4e@redhat.com> References: <7689764e-c0f6-4016-9557-b54cf4a3de4e@redhat.com> Date: Wed, 30 Sep 2026 14:56:27 -0300 Precedence: bulk X-Mailing-List: linux-cifs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Frank Sorenson writes: > I ran xfstests on cifs/cifs-next (7.3-rc3+) with KCSAN enabled, and caught > a number of data races in the smb client. > > The most concerning finding is a structural bitfield aliasing issue in > 'struct cifsFileInfo'. Nice catch. Please take a look at the following fix from Henrique ec306600d5ba ("smb: client: split cached_fid bitfields to avoid shared-byte RMW races") You should probably fix them the same way. Regarding the serialisation on them, yes, we would to check which one really requires it. That could be done separately, too.