From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.netfilter.org (mail.netfilter.org [217.70.190.124]) (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 C65B119ADA2; Tue, 12 Aug 2025 13:02:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.190.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755003765; cv=none; b=XPCL+JIsyMStx0WNtHemGhmDR/EchNP1Xs3OsXN8nwvziqWiZmR98k4Bsbk88ca6WbCRDak3BrTTkKx7ARriyixRlHdZsyQnD56HS4HyHncZCkjwSV8EfGuM+uZLriATjXLKSoUm/XfYvbMhkyY8xK+lRt4L2QDq5JzfvEJsJHE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755003765; c=relaxed/simple; bh=hF4N0ur3iJ8jD2s2cmdeDWXctMqDSnF4apK66vD/nQ0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tLTFAOF42lkXV9YpGqb4yKXhnOwCQRogflN7s8Dk+Doj5zVkGEj4dp/+qF9HBLBCigq4qjpEk+aahSErCxLIAuvgc4proInN1exoYoIABWKCsB6PPj+n2Ux4vLJoRGOQMvQM6X5ToJN+SV40YN+kONjRIl+R10lceYGfWi4WZs8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b=oKY5UMkr; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b=gXIwkCQ1; arc=none smtp.client-ip=217.70.190.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b="oKY5UMkr"; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b="gXIwkCQ1" Received: by mail.netfilter.org (Postfix, from userid 109) id 2824E606FC; Tue, 12 Aug 2025 15:02:41 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1755003761; bh=evoH9a8QCOaR7pv6eWp+7tmYBWdbldvMsHMUrW2jCVI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oKY5UMkrnyeA2SeEorRyk9mEs7SHjXbd7Tb1xNEkkRr2wXL5M6Bu99+V7PapIOFO2 Z/EhzIRls6e+pbNcJuhguVFVR+shSLnNo6/w8LCCEoscDILEayBIMgt91dbv8vwirY 6xtzvap503KI5lM8ClTZV6ULZydgk0sYk8valh01byQ+HopCXKrHMkYBrzY5lsjtpM 3TNiTMrkb3jFYFD5RqGRtaVASyDEdMsIc0eoOmntK2zbgj3ibgh+iPshhsu2U5OINo l7U0cxKmZJQn0jWQTZyaJo6vGtfVpowRYwqdpYMdrme8OFyYCYkH8Us66re76+T3R5 5nvwGQXOJB8Eg== X-Spam-Level: Received: from netfilter.org (mail-agni [217.70.190.124]) by mail.netfilter.org (Postfix) with ESMTPSA id B614A606FC; Tue, 12 Aug 2025 15:02:38 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1755003758; bh=evoH9a8QCOaR7pv6eWp+7tmYBWdbldvMsHMUrW2jCVI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=gXIwkCQ1uYAnGRGAPS+tUxNiGkuBwClHbgrCcxL6V7x5Zw7J5JuivP6EFIzT/KY7J ZQxVm0GA8FueH9ZFdZOUd5xX5irkvrihTxHpUq0AOtF+5R14Yj0GUPRPolmpVJVNks 1PTmTGRtAWzcteGFmEP1bTeJKSoeQDZXja00Oqx19K42szRgWJ1I8i+U9LsfJ0CZ9d ELFB9VlcHJEnfOuiENkO4V5CHmaek8BTxWlKCzqU8cHN7lrM3kRC8dCJXzRzqdcFZu qPFG2MWKGDSHnWtxyifUtW1udgxIZ4vkeljM1iABPjxnV9eefPUjfL1in/LyyhMONH tfApuC6OLLLLg== Date: Tue, 12 Aug 2025 15:02:35 +0200 From: Pablo Neira Ayuso To: Qingfang Deng Cc: Eric Dumazet , Andrew Lunn , "David S. Miller" , Jakub Kicinski , Paolo Abeni , Felix Fietkau , linux-ppp@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net] ppp: fix race conditions in ppp_fill_forward_path Message-ID: References: <20250811084427.178739-1-dqfext@gmail.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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Tue, Aug 12, 2025 at 05:38:02PM +0800, Qingfang Deng wrote: > On Mon, Aug 11, 2025 at 5:35 PM Qingfang Deng wrote: > > > > On Mon, Aug 11, 2025 at 5:19 PM Eric Dumazet wrote: > > > > > > On Mon, Aug 11, 2025 at 1:44 AM Qingfang Deng wrote: > > > It is unclear if rcu_read_lock() is held at this point. > > > > > > list_first_or_null_rcu() does not have a builtin __list_check_rcu() > > > > ndo_fill_forward_path() is called by nf_tables chains, which is inside > > an RCU critical section. > > Update: mtk_flow_get_wdma_info() in mtk_ppe_offload.c calls > dev_fill_forward_path() in process context without RCU, so > ppp_fill_forward_path() can be called from two different contexts. > Should I add rcu_read_lock() to mtk_flow_get_wdma_info() or > ppp_fill_forward_path()? mtk_flow_get_wdma_info() seems to be the exception at this point, so I'm inclined to add rcu_read_lock() to mtk_flow_get_wdma_info().