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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DF999EB64D7 for ; Wed, 14 Jun 2023 03:02:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237865AbjFNDCD (ORCPT ); Tue, 13 Jun 2023 23:02:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44248 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233720AbjFNDBy (ORCPT ); Tue, 13 Jun 2023 23:01:54 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 555B319A for ; Tue, 13 Jun 2023 20:01:53 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E000D63D08 for ; Wed, 14 Jun 2023 03:01:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BD1A7C433C0; Wed, 14 Jun 2023 03:01:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686711712; bh=J+s2slKhai8XoyOcd8BRcW7AAnL/2RowtfWNsgZlnt4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=VJKJOxSM5D1wAB6WYS0ECG7YcHY4zcGi3xYMdXK87fVWyPnP1yKHuF7vWBX970rRG HvyItXpsHSRlde4DzBOZgkq/AQxNawM8PlEiTGXSXaAaX6Rwt73IhTQISgbQTaq+rC prmJR698iP3uo11HIPQrmLyh2pNxTZoMBwqefazReewy3O3hXL9ms2JfEhKYmMXRc6 s57ctjAqRZYnvVtHMq2NYspE040cDeDN8EGDHw9QJVwzXoMnJikrPIff7AwApStkXN 9DTZzPg0zvD6ZLAE32yeN4bWJCLvxVFJXnIsHDNE8/TlDTnOSz50lek7pAyym7RbPF jmDXVjMZ4bu8w== Date: Tue, 13 Jun 2023 20:01:50 -0700 From: Jakub Kicinski To: Fedor Pchelkin Cc: "David S. Miller" , Sabrina Dubroca , Eric Dumazet , Paolo Abeni , Raed Salem , Lior Nahmanson , Saeed Mahameed , Hannes Frederic Sowa , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Alexey Khoroshilov , lvc-project@linuxtesting.org Subject: Re: [PATCH] net: macsec: fix double free of percpu stats Message-ID: <20230613200150.361bc462@kernel.org> In-Reply-To: <20230613192220.159407-1-pchelkin@ispras.ru> References: <20230613192220.159407-1-pchelkin@ispras.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 13 Jun 2023 22:22:20 +0300 Fedor Pchelkin wrote: > Inside macsec_add_dev() we free percpu macsec->secy.tx_sc.stats and > macsec->stats on some of the memory allocation failure paths. However, the > net_device is already registered to that moment: in macsec_newlink(), just > before calling macsec_add_dev(). This means that during unregister process > its priv_destructor - macsec_free_netdev() - will be called and will free > the stats again. > > Remove freeing percpu stats inside macsec_add_dev() because > macsec_free_netdev() will correctly free the already allocated ones. The > pointers to unallocated stats stay NULL, and free_percpu() treats that > correctly. What prevents the device from being opened and used before macsec_add_dev() has finished? I think we need a fix which would move this code before register_netdev(), instead :( -- pw-bot: cr