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 B2C62C433EF for ; Tue, 12 Apr 2022 09:12:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237190AbiDLJO7 (ORCPT ); Tue, 12 Apr 2022 05:14:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358021AbiDLHk7 (ORCPT ); Tue, 12 Apr 2022 03:40:59 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F5463D49F; Tue, 12 Apr 2022 00:17:14 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 8E8D46183C; Tue, 12 Apr 2022 07:17:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F83BC385AE; Tue, 12 Apr 2022 07:17:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649747833; bh=kShmUKhk7LeU0JYZ+RZnv3yHp8XfKe090h2Ncf9GveQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RQ/0G5VyVOHwbSKw9TXBgiSQa/sNRKbj7iS2GN0x39s9rTYCO0maf/7n1jfIJDsK3 Cng8jI39fM82Fl7ZmBFvHzhzVrGg/6y4npVZn346cNUwp2hJ4hXzbXBXYvXXRy7VGY SvX+bSA8PacUAZZXllBiYCMhu5aWWYqTqFBTOs18= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Guilherme G. Piccoli" , Michael Kelley , Wei Liu , Sasha Levin Subject: [PATCH 5.17 195/343] Drivers: hv: vmbus: Fix potential crash on module unload Date: Tue, 12 Apr 2022 08:30:13 +0200 Message-Id: <20220412062956.986128622@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412062951.095765152@linuxfoundation.org> References: <20220412062951.095765152@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Guilherme G. Piccoli [ Upstream commit 792f232d57ff28bbd5f9c4abe0466b23d5879dc8 ] The vmbus driver relies on the panic notifier infrastructure to perform some operations when a panic event is detected. Since vmbus can be built as module, it is required that the driver handles both registering and unregistering such panic notifier callback. After commit 74347a99e73a ("x86/Hyper-V: Unload vmbus channel in hv panic callback") though, the panic notifier registration is done unconditionally in the module initialization routine whereas the unregistering procedure is conditionally guarded and executes only if HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE capability is set. This patch fixes that by unconditionally unregistering the panic notifier in the module's exit routine as well. Fixes: 74347a99e73a ("x86/Hyper-V: Unload vmbus channel in hv panic callback") Signed-off-by: Guilherme G. Piccoli Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220315203535.682306-1-gpiccoli@igalia.com Signed-off-by: Wei Liu Signed-off-by: Sasha Levin --- drivers/hv/vmbus_drv.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 0a05e10ab36c..4bea1dfa41cd 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -2781,10 +2781,15 @@ static void __exit vmbus_exit(void) if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { kmsg_dump_unregister(&hv_kmsg_dumper); unregister_die_notifier(&hyperv_die_block); - atomic_notifier_chain_unregister(&panic_notifier_list, - &hyperv_panic_block); } + /* + * The panic notifier is always registered, hence we should + * also unconditionally unregister it here as well. + */ + atomic_notifier_chain_unregister(&panic_notifier_list, + &hyperv_panic_block); + free_page((unsigned long)hv_panic_page); unregister_sysctl_table(hv_ctl_table_hdr); hv_ctl_table_hdr = NULL; -- 2.35.1