Received: by 2002:a25:d7c1:0:0:0:0:0 with SMTP id o184csp5208669ybg; Mon, 21 Oct 2019 23:14:14 -0700 (PDT) X-Google-Smtp-Source: APXvYqy4MIO7TakRkAvwPTVt+BJK3VSJCQp4+I+TCHFXCh/BaHKV8jsUnSRd3SJoDE7LsyF7badw X-Received: by 2002:a50:b558:: with SMTP id z24mr15842302edd.67.1571724854638; Mon, 21 Oct 2019 23:14:14 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1571724854; cv=none; d=google.com; s=arc-20160816; b=LhZe23JerNWXypaVPngStd67cD+WFng2qmI1zq0EzyEm3FO9Cg3J0XtdS6Kg0Zs1IE y5+99nf7WZ+3DHmkLcSGZ9QO7Oj0z+cqRxz44EZ/wVXbNcnv7JHuYovWCVE2Due7jE7G qyRhBjyDtBscE3+WjA4mryIjevNfoCOWSOIGl24mFazxkluWuXBxufMfV885QsouNnVN nHmMbL4hkuxcGeUGZ5nBl7IeKdBxK1A4qiaOYn665Unhn3zKa+uN3zG+zzdCIhpur/rf 6npw57tRukw7lt7xpnEtsM9KXSMgbahgJgV4ExJBNS1+1hQfsM8NsdoKqvomXl9DGGb7 43PA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date; bh=I4CA4dVsIAdBdxG5C4VRvI0ZiJCs0bfytDdrtxNJI50=; b=Lf5m1JjUOzJwZO1NGsGaJruLxxONQvk0qIpZSIqTN9cxm3GJH+dhiPq1mQntfnenXn PFFfbeCOUJo7gZNZDj8eME31aJ4aP56yohLoNz3YstiSL51RpIoSJo54HSeZnltM9cKq 44tUY0CHDiLsBqp4QN4dw8ekzEBATd+sNVGx7i1a8m7SJGebbh2CkKNpYNcZmqoAmt6h lHy9uvZmUlx+aROPkmvOdJXg309QUNZzdIKxuCdhSXCcIiZTDYhQQbHfVPcfQezFFKce 7x2VtM9BIkNjRhM4FYxWYJtvZMIAMxfXZ3dUh+Uq9BvtdnsvarlmFSPv9I2AAAwOFlit l7gA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id j18si10165091ejv.201.2019.10.21.23.13.51; Mon, 21 Oct 2019 23:14:14 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731057AbfJVGNR (ORCPT + 99 others); Tue, 22 Oct 2019 02:13:17 -0400 Received: from helcar.hmeau.com ([216.24.177.18]:43462 "EHLO deadmen.hmeau.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726082AbfJVGNQ (ORCPT ); Tue, 22 Oct 2019 02:13:16 -0400 Received: from gondobar.mordor.me.apana.org.au ([192.168.128.4] helo=gondobar) by deadmen.hmeau.com with esmtps (Exim 4.89 #2 (Debian)) id 1iMnPl-0001JZ-Ha; Tue, 22 Oct 2019 14:13:05 +0800 Received: from herbert by gondobar with local (Exim 4.89) (envelope-from ) id 1iMnPd-00024y-Qr; Tue, 22 Oct 2019 14:12:57 +0800 Date: Tue, 22 Oct 2019 14:12:57 +0800 From: Herbert Xu To: Tom Rix Cc: Steffen Klassert , davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] xfrm : lock input tasklet skb queue Message-ID: <20191022061257.jft26bvvh24olihs@gondor.apana.org.au> References: <20191021083731.GK15862@gauss3.secunet.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 21, 2019 at 09:31:13AM -0700, Tom Rix wrote: > When preempt rt is full, softirq and interrupts run in kthreads. So it > is possible for the tasklet to sleep and for its queue to get modified > while it sleeps. This is ridiculous. The network stack is full of assumptions like this. So I think we need to fix preempt rt instead because you can't make a major change like this without auditing the entire kernel first rather than relying on a whack-a-mole approach. Cheers, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt