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[198.145.29.99]) by mx.google.com with ESMTPS id cd5si9458713plb.207.2019.05.17.14.37.47 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 17 May 2019 14:37:47 -0700 (PDT) Received-SPF: pass (google.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b="zyaA/h6a"; spf=pass (google.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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?