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=-4.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,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 C2F7FC433C1 for ; Wed, 24 Mar 2021 19:50:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7BAF2619EE for ; Wed, 24 Mar 2021 19:50:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238044AbhCXTuS (ORCPT ); Wed, 24 Mar 2021 15:50:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237807AbhCXTuB (ORCPT ); Wed, 24 Mar 2021 15:50:01 -0400 Received: from mail-lf1-x12c.google.com (mail-lf1-x12c.google.com [IPv6:2a00:1450:4864:20::12c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 44F14C061763 for ; Wed, 24 Mar 2021 12:50:01 -0700 (PDT) Received: by mail-lf1-x12c.google.com with SMTP id b83so33766560lfd.11 for ; Wed, 24 Mar 2021 12:50:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:from:to:cc:references:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=O8cBTKAdHJ0ckCRthe0qr0Y/0P1LRqCmcET2CZxqc7c=; b=lr4xRl9TSCcUHHO5T39ojnZ/k0dwGVHT5yGCtsXyBtkK8xEctwhISxsiVnAYubdD8t uepXFAoTP/5QoMevBO1N3fZayc9a8oEP+4esELAAaYPuJvLGEEy/XxlGWiCGFwM93Q1F vnIjjGUFl+1584HRaHHhwG24dX8LTp/eTzk/kfECOpM7LEUdT51G5jOGmij7cppL3vJt fpzqHQxO4cQupFKSlBzx6g0vFA/UJINMBDIuyvuVfSnrNOk7H50akSE7XrWqtX/kLvU2 ZOeIyonq2gzyMGjMKoSF8O/NgjdMsC5+PpQtf0ACtidU/Je+ff2qBXHNNoSOwbdtRWqm REkg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=O8cBTKAdHJ0ckCRthe0qr0Y/0P1LRqCmcET2CZxqc7c=; b=A3Bzp+kZqQssTw1R8iDvsaBdbMl/ox9KbD+0HvXiOlOoh1elkZmEKYLPpMKnv7bLHd Z5brsMLrJXGf1ldpo15wDYHc8pQnB+6JMTPyavwKxXBkjVcXZC2T9BPckUn9rp00sYwJ 18bT+oLoX3a3JUzMDGIswZnW+SKpmB7L0il5plpnB+gD2bdrEHP/TeYQSYOfvhfe2lr6 BrLTy8wAwG1Dr3OnjRxpImJ6V2HOiWeo+fA7lFX14jeYzT8tCp69SVphIHBpXI9xFIdd wy4KBZG5tZtLUtAtBxYN6XxgY5lrYJ/WXdk0b9ojemRl4SgZhHtW09JG1B3+N7tVhkGS oEVA== X-Gm-Message-State: AOAM530iwmpgBEs0sozO5HQfYIqwFATJw96sv7GJ/3T7D0uT9jrK3D8w 4byP0OPqtg/Pudn+5Ghm6Mc= X-Google-Smtp-Source: ABdhPJwP5pt79NE9N+S388jRM1JPamW66D8sTd20YsY8xlbOLEn3eUK39PCoeRTzgunt3hJ8CTk3fw== X-Received: by 2002:a19:b03:: with SMTP id 3mr2878904lfl.236.1616615399560; Wed, 24 Mar 2021 12:49:59 -0700 (PDT) Received: from [192.168.2.145] (109-252-193-60.dynamic.spd-mgts.ru. [109.252.193.60]) by smtp.googlemail.com with ESMTPSA id y10sm332353lfl.240.2021.03.24.12.49.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 24 Mar 2021 12:49:59 -0700 (PDT) Subject: Re: [PATCH] mm: cma: fix corruption cma_sysfs_alloc_pages_count From: Dmitry Osipenko To: Minchan Kim , Andrew Morton Cc: linux-mm , LKML , gregkh@linuxfoundation.org, surenb@google.com, joaodias@google.com, jhubbard@nvidia.com, willy@infradead.org References: <20210324192044.1505747-1-minchan@kernel.org> <18ee5c3e-fba2-0d8d-bd93-5fb8d0dd7a01@gmail.com> Message-ID: <89ba4c7a-42d2-5412-2367-cc1cffc1117b@gmail.com> Date: Wed, 24 Mar 2021 22:49:58 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <18ee5c3e-fba2-0d8d-bd93-5fb8d0dd7a01@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.