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=-1.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=ham 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 241DAC04AB4 for ; Fri, 17 May 2019 21:37:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C5ED32082E for ; Fri, 17 May 2019 21:37:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558129068; bh=aV+DZYgCxz6TeUuopFM95pRHxHKcPxgDyN99N5XYJko=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=ICZgZgKC2sAlc0viNP+FrQ1JzB4hpe7UR87CxxUn4aDbwGG+xk6kE/ioOTAHoofe5 nnQu1PFuET/wH5H3g1yCGEYDqXDOQSvvYneTXIdTSMVD+GRM9WLxhJAQ6mZsdKtuGE 6ZuimxKoNr7qZIduu4c8lySd01XGpETVd4WWIH1w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729521AbfEQVhr (ORCPT ); Fri, 17 May 2019 17:37:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:44084 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726960AbfEQVhr (ORCPT ); Fri, 17 May 2019 17:37:47 -0400 Received: from akpm3.svl.corp.google.com (unknown [104.133.8.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E79DB20815; Fri, 17 May 2019 21:37:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558129067; bh=aV+DZYgCxz6TeUuopFM95pRHxHKcPxgDyN99N5XYJko=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=zyaA/h6aSWnQbfVIYgqsy2UrDKSlqT0fUgWvQgq/rIbENLvBDNuAhY84I4Cm0CmLD cPGqFAtx/nnBYevpcWHQItaMk+wpufHLo0tSppdBJA4ooerLdUqPl1v/gMovZc1ya9 Y/ZZQIjHjuO4Er8F1QTdG0soYL1cGA93941vJyYY= Date: Fri, 17 May 2019 14:37:46 -0700 From: Andrew Morton To: Dmitry Vyukov Cc: catalin.marinas@arm.com, Dmitry Vyukov , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] kmemleak: fix check for softirq context Message-Id: <20190517143746.2157a759f65b4cbc73321124@linux-foundation.org> In-Reply-To: <20190517171507.96046-1-dvyukov@gmail.com> References: <20190517171507.96046-1-dvyukov@gmail.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 17 May 2019 19:15:07 +0200 Dmitry Vyukov wrote: > From: Dmitry Vyukov > > in_softirq() is a wrong predicate to check if we are in a softirq context. > It also returns true if we have BH disabled, so objects are falsely > stamped with "softirq" comm. The correct predicate is in_serving_softirq(). > > ... > > --- a/mm/kmemleak.c > +++ b/mm/kmemleak.c > @@ -588,7 +588,7 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size, > if (in_irq()) { > object->pid = 0; > strncpy(object->comm, "hardirq", sizeof(object->comm)); > - } else if (in_softirq()) { > + } else if (in_serving_softirq()) { > object->pid = 0; > strncpy(object->comm, "softirq", sizeof(object->comm)); > } else { What are the user-visible runtime effects of this change?