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=-4.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 8D1F3C433E2 for ; Wed, 24 Mar 2021 19:58:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 671F861A27 for ; Wed, 24 Mar 2021 19:58:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238036AbhCXT5u (ORCPT ); Wed, 24 Mar 2021 15:57:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36898 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238002AbhCXT5t (ORCPT ); Wed, 24 Mar 2021 15:57:49 -0400 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CCB2DC061763 for ; Wed, 24 Mar 2021 12:57:48 -0700 (PDT) Received: by mail-pf1-x42b.google.com with SMTP id j25so18190578pfe.2 for ; Wed, 24 Mar 2021 12:57:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=6wje3u9/LXf+fY5O7zx9Tl/wzeXgMCXQSJ1thmeKKYE=; b=UXnapM+uUzWVFHRiBlLLL1zWvGJKqjoZF2CvY3BY7ukyM1pwtw9wFyNYL/bugsIi5H 1fd+dM1XyXiniMl2xByDVLvLwUEALXjQ5RIr7lhx6bymj8e/i68g1k2Ojjg5e3/cVkai 92hByEyaYIfObfW/yEOAQGbVxV36E6HqKgePvZq17Ab1SIUFr6Smi/sL1/SoJXCAcntH sokHXuZrupuVmCjDHXWJEAXzh/HDPTNLpgo52MtaW8359nAJiuF4BFOvcF/4mqyZAGmH KJFaZt5VmGPDDDMQRkMykO2daw9YWHWayZ3J/YJXVwDY31VYa92jNpblNQIqkUj1Xnr3 wqJQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition :content-transfer-encoding:in-reply-to; bh=6wje3u9/LXf+fY5O7zx9Tl/wzeXgMCXQSJ1thmeKKYE=; b=UXsu2ZChiqDkGrkl+lq+GWMw+a32eCLYRMSrN1nd1iisqdYLCjV6sQDG7nZL2aNI+F 5q+PKRok8BQIVdLkhNHxThivYuSGE+OCEwzDii5UEiqcIDvaCyBwKipOrn7wlh0oYLyk lUsFAJD84Of0m9tJGZVHYjiyIJohdclhVoQG6iVRO8SKG2wD/HUUVrRsS5qNxgpmbnb9 0Iv9Ti7eWU5Q6VlW0p03WK3KkUWgEgofqPs32lIFKgu65SrQLk74jLPVV5SuKrxUhLAV zGHb53zsZVPv91vZcut1qQEzrcbDn4BXMzs43LnC3OyxpgGWO+l1Y4nb2gYxnB//Obwm Xg4A== X-Gm-Message-State: AOAM532dt0y4ecv0Mjio0Fly9E8GjxF+/GHLTmfd7oTzg3VTCRlyGy+X MDMoqEM6NvssN0FjULyDV7A= X-Google-Smtp-Source: ABdhPJyuSSTR7hFg4UxeOh1mBDNhBv6Kz8XMiQUHzSnDVQ8723pC26jcLbkhDhxaBOjWDHyaU6B40A== X-Received: by 2002:aa7:980a:0:b029:20c:5402:5de9 with SMTP id e10-20020aa7980a0000b029020c54025de9mr4708822pfl.18.1616615868433; Wed, 24 Mar 2021 12:57:48 -0700 (PDT) Received: from google.com ([2620:15c:211:201:7dfa:1e53:536:7976]) by smtp.gmail.com with ESMTPSA id e8sm3314971pgb.35.2021.03.24.12.57.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 24 Mar 2021 12:57:47 -0700 (PDT) Sender: Minchan Kim Date: Wed, 24 Mar 2021 12:57:45 -0700 From: Minchan Kim To: Dmitry Osipenko Cc: Andrew Morton , linux-mm , LKML , gregkh@linuxfoundation.org, surenb@google.com, joaodias@google.com, jhubbard@nvidia.com, willy@infradead.org Subject: Re: [PATCH] mm: cma: fix corruption cma_sysfs_alloc_pages_count Message-ID: References: <20210324192044.1505747-1-minchan@kernel.org> <18ee5c3e-fba2-0d8d-bd93-5fb8d0dd7a01@gmail.com> <89ba4c7a-42d2-5412-2367-cc1cffc1117b@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <89ba4c7a-42d2-5412-2367-cc1cffc1117b@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 24, 2021 at 10:49:58PM +0300, Dmitry Osipenko wrote: > 24.03.2021 22:43, Dmitry Osipenko пишет: > > 24.03.2021 22:20, Minchan Kim пишет: > >> static int __init cma_sysfs_init(void) > >> { > >> - int i = 0; > >> + struct kobject *cma_kobj_root; > >> + struct cma_kobject *cma_kobj; > >> struct cma *cma; > >> + unsigned int i; > > > >> while (--i >= 0) { > > > > Do you realize that this doesn't work anymore? > > > >> cma = &cma_areas[i]; > >> - kobject_put(&cma->stat->kobj); > >> - } > >> > >> - kfree(cma_stats); > >> - kobject_put(cma_kobj); > >> + kobject_put(&cma->cma_kobj->kobj); > >> + kfree(cma->cma_kobj); > > > > Freeing a null pointer? > > > >> + cma->cma_kobj = NULL; > >> + } > >> + kobject_put(cma_kobj_root); > > > > Please try to simulate the errors and check that error path is working > properly in the next version. > > Alternatively, we could remove the cma_kobj_release entirely, like Greg > suggested previously, and then don't care about cleaning up at all. Does he suggested it to remove cma_kobj_release?(Initially, I did but was rejected from Greg)