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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 3AB2CCA9EAE for ; Tue, 29 Oct 2019 13:14:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0C5D520856 for ; Tue, 29 Oct 2019 13:14:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572354844; bh=Wsiy/Oyn68kJTlT7TJp/MY8Xp0/pOI5Gi9qp0DGQdWk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=YrFJzd3ausPAFTC+5eqsBMRcEB5eHqhrNP2DXmlAwk/8/kQ/qz8ZiofKbXHB2kBu3 gOMhyEbCCwijz4AgjepMPCktXmXkktzu3gWaoyPJZIDCithvnB6V2cek1zGT9xHpVC SHuwx/qvHnwmkmxhvlAkpbkXADjY5NmZxnnQnJOE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388098AbfJ2NOD (ORCPT ); Tue, 29 Oct 2019 09:14:03 -0400 Received: from mx2.suse.de ([195.135.220.15]:41592 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732534AbfJ2NOD (ORCPT ); Tue, 29 Oct 2019 09:14:03 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 00693AC31; Tue, 29 Oct 2019 13:14:00 +0000 (UTC) Date: Tue, 29 Oct 2019 14:13:58 +0100 From: Michal Hocko To: coverity-bot Cc: Johannes Weiner , "David S. Miller" , Andrew Morton , Vladimir Davydov , Linus Torvalds , "Gustavo A. R. Silva" , linux-next@vger.kernel.org Subject: Re: Coverity: reclaim_high(): Error handling issues Message-ID: <20191029131358.GM31513@dhcp22.suse.cz> References: <201910281604.EC4A108@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201910281604.EC4A108@keescook> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-next-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-next@vger.kernel.org On Mon 28-10-19 16:04:23, Kees Cook wrote: > Hello! > > This is an experimental automated report about issues detected by Coverity > from a scan of next-20191025 as part of the linux-next weekly scan project: > https://scan.coverity.com/projects/linux-next-weekly-scan > > You're getting this email because you were associated with the identified > lines of code (noted below) that were touched by recent commits: > > f7e1cb6ec51b ("mm: memcontrol: account socket memory in unified hierarchy memory controller") JFTR This seems misleading wrt to the issue reported here AFAICS. The code was there even before this commit. > Coverity reported the following: > > *** CID 1487368: Error handling issues (CHECKED_RETURN) > /mm/memcontrol.c: 2343 in reclaim_high() > 2337 gfp_t gfp_mask) > 2338 { > 2339 do { > 2340 if (page_counter_read(&memcg->memory) <= memcg->high) > 2341 continue; > 2342 memcg_memory_event(memcg, MEMCG_HIGH); > vvv CID 1487368: Error handling issues (CHECKED_RETURN) > vvv Calling "try_to_free_mem_cgroup_pages" without checking return value (as is done elsewhere 5 out of 6 times). > 2343 try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, true); Yes we do not check for the return value here because the high limit is a best effort feature. A more highlevel throttling which is not based on the reclaim directly is implemented in mem_cgroup_handle_over_high > 2344 } while ((memcg = parent_mem_cgroup(memcg))); > 2345 } > 2346 > 2347 static void high_work_func(struct work_struct *work) > 2348 { > > If this is a false positive, please let us know so we can mark it as > such, or teach the Coverity rules to be smarter. If not, please make > sure fixes get into linux-next. :) For patches fixing this, please > include: > > Reported-by: coverity-bot > Addresses-Coverity-ID: 1487368 ("Error handling issues") > Fixes: f7e1cb6ec51b ("mm: memcontrol: account socket memory in unified hierarchy memory controller") > > > Thanks for your attention! > > -- > Coverity-bot -- Michal Hocko SUSE Labs