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=-4.2 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,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 43F2BC433E0 for ; Thu, 18 Mar 2021 17:00:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0325764DD8 for ; Thu, 18 Mar 2021 17:00:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231972AbhCRQ7p (ORCPT ); Thu, 18 Mar 2021 12:59:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58710 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230338AbhCRQ7N (ORCPT ); Thu, 18 Mar 2021 12:59:13 -0400 Received: from mail-lj1-x22d.google.com (mail-lj1-x22d.google.com [IPv6:2a00:1450:4864:20::22d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 55C02C06174A for ; Thu, 18 Mar 2021 09:59:13 -0700 (PDT) Received: by mail-lj1-x22d.google.com with SMTP id u20so8338204lja.13 for ; Thu, 18 Mar 2021 09:59:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=YMrggABsnZJ+ZXH9liZmlQCij8GSsr394Gpx+UK66oA=; b=Jeut3itmky30azxyzWFWMjRvFxF+exGrDtA9srFYbGOwBYPtZAgkwCYNvPclFzpEWV 6uprkOejOZQMLRwiJqFqxHqudVreaMMESCdqidv4FUM4fJBNJPf/sdwudvWZul8q99Wj tlaa6jM7zZUJqLdE+jsaJ+by6GggNpaKVbwIIX60pA8Ww0BsANcJQ/igVik2FOqqYSkc /E8t+g5fzeFyj51OirThPVImdERuU8nhIFdwFjg4BQQupLF9vcrtB+y9lsbRAKPqpKZ4 xinL8ONnXH07fwWzLbmgBopI/gwjtOz2Akn7VB8CR7t257PjfQNK6mjKa1mvj5FNR+kv dTAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=YMrggABsnZJ+ZXH9liZmlQCij8GSsr394Gpx+UK66oA=; b=cUfJvOveGydGd2MXVgbmZc5KDLxwa7xbBXryI3nb5HbyRE0tkI0qzVLj00pQIrkIWB itgft8t3wm7b5/jL/PvE/BnpPqCc/X+KXmG4ER+llf2aAC1k3vaJxI6c85KA4c4jWf0V SmcJsvJpX3Hy0LoPkjYFT+vwYCPOxpyOW+pE+kYWWBGMRDD9Wb4PTPzc3iUDGDDHi8zC wILpDdaA9m9VNColrOl21gsg0SMKUGQuGwI+DDe88QCfSTPd6ecK76ycCXrvY8s9v/xV srUW2XKVTAU5Kn1Esq+6o7P3Jh3cS7kG/MaT/BDZDBAcQ61K5/DvjRKyu+A7b73bbiEx A4Fw== X-Gm-Message-State: AOAM5301jC+mw3yt5rYbOB/qGIW9pVOfoiFvCvMTjw+rOdnAEZzosrqm yyiO9qLJlXJUiKXOMzWNERMPFMdpXbc= X-Google-Smtp-Source: ABdhPJxI9vhvprPuimBHRjKQuE2wRnNH3gIGfmc85DlGSsaBDpd37m0Poo1nSvgbpfib/Hq+qefIgA== X-Received: by 2002:a2e:9a98:: with SMTP id p24mr6001300lji.265.1616086750123; Thu, 18 Mar 2021 09:59:10 -0700 (PDT) Received: from pc638.lan (h5ef52e3d.seluork.dyn.perspektivbredband.net. [94.245.46.61]) by smtp.gmail.com with ESMTPSA id d8sm286841lfa.49.2021.03.18.09.59.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Mar 2021 09:59:09 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Thu, 18 Mar 2021 17:59:07 +0100 To: vjitta@codeaurora.org Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, vinmenon@codeaurora.org Subject: Re: [PATCH] mm: vmalloc: Prevent use after free in _vm_unmap_aliases Message-ID: <20210318165907.GA10448@pc638.lan> References: <1616062105-23263-1-git-send-email-vjitta@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1616062105-23263-1-git-send-email-vjitta@codeaurora.org> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 18, 2021 at 03:38:25PM +0530, vjitta@codeaurora.org wrote: > From: Vijayanand Jitta > > A potential use after free can occur in _vm_unmap_aliases > where an already freed vmap_area could be accessed, Consider > the following scenario: > > Process 1 Process 2 > > __vm_unmap_aliases __vm_unmap_aliases > purge_fragmented_blocks_allcpus rcu_read_lock() > rcu_read_lock() > list_del_rcu(&vb->free_list) > list_for_each_entry_rcu(vb .. ) > __purge_vmap_area_lazy > kmem_cache_free(va) > va_start = vb->va->va_start Or maybe we should switch to kfree_rcu() instead of kmem_cache_free()? -- Vlad Rezki