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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 BBA4BC4360C for ; Sat, 28 Sep 2019 22:04:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 92EED20880 for ; Sat, 28 Sep 2019 22:04:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569708259; bh=+LR3RvDm+2ZImZYU0glSfuRvJ341Rv5LciFQr6Cy6wA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=qcqhpW3Q6VTLLaczDm8UH0tQd4YUwyArrOCQ2wpTitf00hC54+jQY5yh7zSb+iJ6y DuQcPp+eTlF8ypThk5HY2Z+/uY5CvQ24BCgpTjvtfKdonI5QaLOBGJm/5NBz8ejAHh R7+rZp4oNWaDzzc0k9mytFKWVlFdrBCfaDQUYekM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728829AbfI1WEM (ORCPT ); Sat, 28 Sep 2019 18:04:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:52394 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728717AbfI1WEM (ORCPT ); Sat, 28 Sep 2019 18:04:12 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 EC92F20866; Sat, 28 Sep 2019 22:04:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569708251; bh=+LR3RvDm+2ZImZYU0glSfuRvJ341Rv5LciFQr6Cy6wA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Scf4bwAi5HaX4X8cVyqnzFCGblAgIqSzzPiGp8HzS33jbEOYbplOkEUjSBucQxE0m e2AiKx++r8+hyzaKXCbkw8k0wMyrCtVs4R+ZPbWEKmA7tJF+d4hty+Hy7Bl5PM47RA WIfNUHmdF3xcenKQzW66jKe2p5qc+yrXyECXfxbk= Date: Sat, 28 Sep 2019 15:04:10 -0700 From: Andrew Morton To: Matthew Wilcox Cc: Dan Carpenter , Greg Kroah-Hartman , Andy Shevchenko , tglx@linutronix.de, Enrico Weigelt , Kate Stewart , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH] mm, vmpressure: Fix a signedness bug in vmpressure_register_event() Message-Id: <20190928150410.5964a7935ca1b3cb47a2ae76@linux-foundation.org> In-Reply-To: <20190928214702.GA30382@bombadil.infradead.org> References: <20190925110449.GO3264@mwanda> <20190928142356.932cff0ad6c17f4a18edc80f@linux-foundation.org> <20190928214702.GA30382@bombadil.infradead.org> X-Mailer: Sylpheed 3.5.1 (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 Sat, 28 Sep 2019 14:47:02 -0700 Matthew Wilcox wrote: > On Sat, Sep 28, 2019 at 02:23:56PM -0700, Andrew Morton wrote: > > How about doing it this way? Only copy the int to the enum once we > > know it's within range? > > This will return a positive integer on success instead of 0. We need: > > mutex_unlock(&vmpr->events_lock); > + ret = 0; > out: > > with that, > > Reviewed-by: Matthew Wilcox (Oracle) > > How about further adding ... > > + * Return: 0 on success, -ENOMEM on memory failure or -EINVAL if @args could > + * not be parsed. Cool. --- a/mm/vmpressure.c~mm-vmpressure-fix-a-signedness-bug-in-vmpressure_register_event-fix-fix +++ a/mm/vmpressure.c @@ -355,6 +355,9 @@ void vmpressure_prio(gfp_t gfp, struct m * "hierarchy" or "local"). * * To be used as memcg event method. + * + * Return: 0 on success, -ENOMEM on memory failure or -EINVAL if @args could + * not be parsed. */ int vmpressure_register_event(struct mem_cgroup *memcg, struct eventfd_ctx *eventfd, const char *args) @@ -402,6 +405,7 @@ int vmpressure_register_event(struct mem mutex_lock(&vmpr->events_lock); list_add(&ev->node, &vmpr->events); mutex_unlock(&vmpr->events_lock); + ret = 0; out: kfree(spec_orig); return ret; _