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 B19591B253B; Mon, 9 Sep 2024 14:35:51 +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=1725892551; cv=none; b=RROIkZ7cPot5Ub0ZyAgtaeiNjt4Zzsa66UTJr8DE8dAqCem5LLDQutPbsRLO15+B23BmKwaJG99znSGEyZO7pYJ5PbKFCJe3zW+8d45X3AflwJMRzF8RK9O/dSBv6hGI7IuIF5nRlIVfZygDI9Y/26Er4PgmKX10i6x0Y+KmW70= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725892551; c=relaxed/simple; bh=FZKxzFRyz9Op8EvuEP3cZ3bXtDG2HWdMHdwMe2g59vw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=eI89YzlqKPco/tn6esbodzduIpvOGGaVRR+u7VsGS/kvjlHEtHOFGoLrfx28Xv1QTLHathTlGiO9ewI0q9XfnTeNdFeNgZxG8pNYLUoQuu4IGtsQiGjtDDLoYvSNOZ0N2Stv6hdtmucKOPNAKT4r/l/r3R+cIJ4gsxWqmNuyKKo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=s1v7sjN3; 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="s1v7sjN3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A70D5C4CEC5; Mon, 9 Sep 2024 14:35:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725892551; bh=FZKxzFRyz9Op8EvuEP3cZ3bXtDG2HWdMHdwMe2g59vw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=s1v7sjN3LNrEZl6o3gbfDHJL/srLbCjmQhFTT9iKdRjFei0qYil6a8RA/j709kphV 5dt/5lLGlU4JUEf9HDqXDA13POjv3B1tsyQkm6HxD+ogSgqSlk2+fiDnRPWYcae0le E2/MgNhSOdJxBj5n/kowlKW1eAEzlfAhR66Qb+Qjalo8Nh1XuS01FvByl1Gv6CVO+b cBcNQMbEgp5Am40Xxh57lCui4kSPYtYgztxxydnF+MrtWp6rmQZM8HRjdAeoJKeyWz xkIwGRbL4dHCn0baIOZLiV4oILm1sVaSbi3zL6AqG79UPOnkNp2EDRKThVLbpQr2Bf I2TFUukUj/OqQ== Date: Mon, 9 Sep 2024 15:35:46 +0100 From: Simon Horman To: Marc Kleine-Budde Cc: Nathan Chancellor , kernel@pengutronix.de, Vincent Mailhol , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Heiko Stuebner , linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, llvm@lists.linux.dev, patches@lists.linux.dev Subject: Re: [PATCH] can: rockchip_canfd: fix return type of rkcanfd_start_xmit() Message-ID: <20240909143546.GX2097826@kernel.org> References: <20240906-rockchip-canfd-wifpts-v1-1-b1398da865b7@kernel.org> <20240909084448.GU2097826@kernel.org> <20240909-arcane-practical-petrel-015d24-mkl@pengutronix.de> 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: <20240909-arcane-practical-petrel-015d24-mkl@pengutronix.de> On Mon, Sep 09, 2024 at 10:57:06AM +0200, Marc Kleine-Budde wrote: > On 09.09.2024 09:44:48, Simon Horman wrote: > > On Fri, Sep 06, 2024 at 01:26:41PM -0700, Nathan Chancellor wrote: > > > With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), > > > indirect call targets are validated against the expected function > > > pointer prototype to make sure the call target is valid to help mitigate > > > ROP attacks. If they are not identical, there is a failure at run time, > > > which manifests as either a kernel panic or thread getting killed. A > > > warning in clang aims to catch these at compile time, which reveals: > > > > > > drivers/net/can/rockchip/rockchip_canfd-core.c:770:20: error: incompatible function pointer types initializing 'netdev_tx_t (*)(struct sk_buff *, struct net_device *)' (aka 'enum netdev_tx (*)(struct sk_buff *, struct net_device *)') with an expression of type 'int (struct sk_buff *, struct net_device *)' [-Werror,-Wincompatible-function-pointer-types-strict] > > > 770 | .ndo_start_xmit = rkcanfd_start_xmit, > > > | ^~~~~~~~~~~~~~~~~~ > > > > > > ->ndo_start_xmit() in 'struct net_device_ops' expects a return type of > > > 'netdev_tx_t', not 'int' (although the types are ABI compatible). Adjust > > > the return type of rkcanfd_start_xmit() to match the prototype's to > > > resolve the warning. > > > > > > Fixes: ff60bfbaf67f ("can: rockchip_canfd: add driver for Rockchip CAN-FD controller") > > > Signed-off-by: Nathan Chancellor > > > > Thanks, I was able to reproduce this problem at build time > > and that your patch addresses it. > > FTR: the default clang in Debian unstable, clang-16.0.6 doesn't support > this. With clang-20 from experimental it works, haven't checked older > versions, though. FTR: I checked using 18.1.8 from here [1][2]. [1] https://mirrors.edge.kernel.org/pub/tools/llvm/ [2] https://mirrors.edge.kernel.org/pub/tools/llvm/files/