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[2620:137:e000::1:20]) by mx.google.com with ESMTP id f33-20020a631f21000000b00434fe5aaf47si3296173pgf.714.2022.09.27.17.54.12; Tue, 27 Sep 2022 17:54:23 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=fEP2im6s; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229818AbiI1A0f (ORCPT + 99 others); Tue, 27 Sep 2022 20:26:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229567AbiI1A0W (ORCPT ); Tue, 27 Sep 2022 20:26:22 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 097F5D4AAE; Tue, 27 Sep 2022 17:26:21 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 8A92CB81E3B; Wed, 28 Sep 2022 00:26:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 18053C433D6; Wed, 28 Sep 2022 00:26:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1664324779; bh=jGniGtl3LSg2UQcTQAQhK2coEuaQhXHf8hbCfu07B4c=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=fEP2im6sdl2dYYrSH86YGCJEIh+7whof9wI0Hg7ln6oaJsq+cxtAMKX4vXc8uetHY Hpepo9+BxVpVOagPPULpB+cQTNcx+8V30lGXkeedxiccGCzjGU69cbpZ3BKXlL3tNg +LiekR2dFQF+ENi0BhFTaEmzlFhEhFuCRDQzn+K2RW5H9Hge8cluznZEbEvvaZHgZ1 xhg8nWPc7Eso4c5FVj5gzuUXUM6EJkCE+LykTpsvjAFCiJWZ+6s0IKbIpePI/9hPM7 N4InSs3TjSvNQ8fEMlPSjK/REY4NENNBXzCgu2/PXTi4e85RAAyeS7i2g0RUttD3Lj obiFCiG4WP19A== Date: Tue, 27 Sep 2022 17:26:18 -0700 From: Jakub Kicinski To: Duoming Zhou Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, isdn@linux-pingi.de Subject: Re: [PATCH V3] mISDN: fix use-after-free bugs in l1oip timer handlers Message-ID: <20220927172618.58f238d6@kernel.org> In-Reply-To: <20220924021842.71754-1-duoming@zju.edu.cn> References: <20220924021842.71754-1-duoming@zju.edu.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-7.2 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 24 Sep 2022 10:18:42 +0800 Duoming Zhou wrote: > + del_timer_sync(&hc->keep_tl); > + del_timer_sync(&hc->timeout_tl); > + cancel_work_sync(&hc->workq); > + del_timer_sync(&hc->keep_tl); > cancel_work_sync(&hc->workq); Why not add a bit which will indicate that the device is shutting down and check it in places which schedule the timer? I think that's much easier to reason about and we won't need to do this rep cancel procedure.