From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A3476C433E1 for ; Fri, 21 Aug 2020 08:59:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 838EB207DF for ; Fri, 21 Aug 2020 08:59:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="k9QSszUW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727941AbgHUI7Y (ORCPT ); Fri, 21 Aug 2020 04:59:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725948AbgHUI7Y (ORCPT ); Fri, 21 Aug 2020 04:59:24 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FDBCC061385; Fri, 21 Aug 2020 01:59:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=uopZNaU4cxTyHr7XErQw6ljqaXqVh1WJtny7IaWd5EU=; b=k9QSszUWMXD5l4y3K3nYTu/j6m GJR9R8uU0Mt3VajQ6Dw809W31cZnyEta6CIpIfw+AdlDrH0kX1bbNUtOEcdnBgiW/kIUnhaM2E72G HKH6qn4iwzqYPXJOs936HaQcyCnuEynsn63BbQSELfNoI6cbZYa1Y5jlbZA98cQOAwZH8x5YAd13X K2f0VCxOlQDkg4077nHGxCGAjazAjK+prwNGVdb3VYBE0C1JflQ+cSDt7XzhJZ2JSuuJYXUc1Fxk9 OXSxl4Ve9tuo3fvSKw3lRabYEweYaEnBKb7QbWn4K7LRXNDUrDiPsmtt1H7nj73eBMcb8IB1tB9KP gpNhx2Xw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1k92tA-0007u1-U0; Fri, 21 Aug 2020 08:59:09 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D09A0305815; Fri, 21 Aug 2020 10:59:07 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 89DDA2B649913; Fri, 21 Aug 2020 10:59:07 +0200 (CEST) Date: Fri, 21 Aug 2020 10:59:07 +0200 From: peterz@infradead.org To: Marco Elver Cc: linux-kernel@vger.kernel.org, davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org, Steven Rostedt , Eric Dumazet Subject: Re: [PATCH] random32: Use rcuidle variant for tracepoint Message-ID: <20200821085907.GJ1362448@hirez.programming.kicks-ass.net> References: <20200821063043.1949509-1-elver@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200821063043.1949509-1-elver@google.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Aug 21, 2020 at 08:30:43AM +0200, Marco Elver wrote: > With KCSAN enabled, prandom_u32() may be called from any context, > including idle CPUs. > > Therefore, switch to using trace_prandom_u32_rcuidle(), to avoid various > issues due to recursion and lockdep warnings when KCSAN and tracing is > enabled. At some point we're going to have to introduce noinstr to idle as well. But until that time this should indeed cure things.