Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752078AbdC0IZH (ORCPT ); Mon, 27 Mar 2017 04:25:07 -0400 Received: from merlin.infradead.org ([205.233.59.134]:45756 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751406AbdC0IZC (ORCPT ); Mon, 27 Mar 2017 04:25:02 -0400 Date: Mon, 27 Mar 2017 10:24:40 +0200 From: Peter Zijlstra To: Nicholas Mc Guire Cc: Ingo Molnar , Rusty Russell , Nick Piggin , linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched/core: switch to BUG_ON() Message-ID: <20170327082440.6lvb7il66mzdaij5@hirez.programming.kicks-ass.net> References: <1490600446-1774-1-git-send-email-der.herr@hofr.at> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1490600446-1774-1-git-send-email-der.herr@hofr.at> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 800 Lines: 21 On Mon, Mar 27, 2017 at 09:40:46AM +0200, Nicholas Mc Guire wrote: > Found by coccinelle: bugon.cocci > ./kernel/sched/core.c:5913:2-5: WARNING: Use BUG_ON instead of if condition followed by BUG. Right, so I disagree with that here. > @@ -5909,8 +5909,8 @@ void __init sched_init_smp(void) > mutex_unlock(&sched_domains_mutex); > > /* Move init over to a non-isolated CPU */ > - if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) > - BUG(); > + BUG_ON(set_cpus_allowed_ptr(current, non_isolated_cpus) < 0); > + > sched_init_granularity(); > free_cpumask_var(non_isolated_cpus); If the condition were without side effects, that pattern would hold, but here the function call set_cpus_allowed_ptr() is very much not a pure function, so wrapping it in a BUG_ON() just fels wrong.