From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D5674345754; Thu, 29 Jan 2026 16:55:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769705706; cv=none; b=u4qgcRQEI4W0cmYkHNolAELe/ePgziXqVOYV9R3r6SyV3fdD/kyZyW58Cx+K0X/sNEV/xEiERsDazOrhJRNGEvuy2hN3FM0xp0JPkpgHXNZiLLy6bKlNQlaoWyKKtD8AXj39jG7Ue0JbAtOI5vNa/4pznOPJqTml2QYEZzW5v+k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769705706; c=relaxed/simple; bh=b5kipVY4HnifU2Q4aFa3jAY1I6v7pAXcmmwljQ7L7DE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XYigAIrM/aYbi69pWfKNaq/TunaKQDbCPTbEwZMiA+wZVxvrik+f7k1/ApyARU9JyQBVoNzurKgCozDBvJi9b5puvSo+AD8Vb3SdJv97tyKj2Qd2QIkIdcUxkWcxxGIjif9vcLiwkPzplPCfIfRYNvIEZ3xfczeNPohyHcBPbC0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jI7pA1Rc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jI7pA1Rc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2AE4AC19422; Thu, 29 Jan 2026 16:55:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769705706; bh=b5kipVY4HnifU2Q4aFa3jAY1I6v7pAXcmmwljQ7L7DE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jI7pA1Rc5/Dsw+MKhJQ9Ql9y2yDwPSDXinSbL1JvcRExPZE9057wZ0JQsHIj+9VcK ClhzCdmKqzcVb93KxDWgvX4t6qW8mqmLCKKyy0oj8w725n3mWU81QvkbbChcxj4RML SjtUvFmfdOeNTzK/HNy38UI5p75OqAk80+4RcOzknUqbEBoEQQaDk9bInKm9qOheJd e5sAG/HaiiA9hEjoq6E79OIzu/UegpL7GdHAEMxy/9n7v+dwAbfNkwjt45irkwzvJA 0TiDdouSo2Rav1jkkM9y9U+vpMf8zpaUsV0rl8e4sfOObkW2PlB63vxvuB18UFOjlt nAM6a7u6mmJIQ== Date: Thu, 29 Jan 2026 16:55:00 +0000 From: Simon Horman To: "D. Wythe" Cc: "David S. Miller" , Dust Li , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Sidraya Jayagond , Wenjia Zhang , Mahanta Jambigi , Tony Lu , Wen Gu , linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org, oliver.yang@linux.alibaba.com, Al Viro Subject: Re: [PATCH net] Revert "net/smc: Introduce TCP ULP support" Message-ID: References: <20260128055452.98251-1-alibuda@linux.alibaba.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260128055452.98251-1-alibuda@linux.alibaba.com> On Wed, Jan 28, 2026 at 01:54:52PM +0800, D. Wythe wrote: > This reverts commit d7cd421da9da2cc7b4d25b8537f66db5c8331c40. > > As reported by Al Viro, the TCP ULP support for SMC is fundamentally > broken. The implementation attempts to convert an active TCP socket > into an SMC socket by modifying the underlying `struct file`, dentry, > and inode in-place, which violates core VFS invariants that assume > these structures are immutable for an open file, creating a risk of > use after free errors and general system instability. > > Given the severity of this design flaw and the fact that cleaner > alternatives (e.g., LD_PRELOAD, BPF) exist for legacy application > transparency, the correct course of action is to remove this feature > entirely. > > Fixes: d7cd421da9da ("net/smc: Introduce TCP ULP support") > Link: https://lore.kernel.org/netdev/Yus1SycZxcd+wHwz@ZenIV/ > Reported-by: Al Viro > Signed-off-by: D. Wythe > Reviewed-by: Tony Lu > Reviewed-by: Dust Li Reviewed-by: Simon Horman