From patchwork Tue Apr 12 06:29:11 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 560630 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 B9DFDC433EF for ; Tue, 12 Apr 2022 07:07:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242096AbiDLHKE (ORCPT ); Tue, 12 Apr 2022 03:10:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352140AbiDLHEz (ORCPT ); Tue, 12 Apr 2022 03:04:55 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5040D46B37; Mon, 11 Apr 2022 23:47:44 -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 2A3F76103A; Tue, 12 Apr 2022 06:47:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3704BC385A6; Tue, 12 Apr 2022 06:47:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649746063; bh=GPMcE/Z5TPn8lD0AfTRMCJGO/tcYseOLuUzJh3fgWPQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sHuWzAhJvtVUejlAeCWhcVp4oEMkeSWMA+u6qK5KNN0yH1ou9Ns4CDCKG5y6RBzah v27VNCYqjskC7zfddBSHtZ/WGB0grJnp+ZrmtzovyjOMyT8cPk/Cp6Hsjjb2tnKtkm Q+kYG7feYsfZiS4m29g00uD2xvIcHPHdC4arZD9o= 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 5.15 148/277] Drivers: hv: vmbus: Fix potential crash on module unload Date: Tue, 12 Apr 2022 08:29:11 +0200 Message-Id: <20220412062946.319702271@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412062942.022903016@linuxfoundation.org> References: <20220412062942.022903016@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 44bd0b6ff505..a939ca1a8d54 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -2776,10 +2776,15 @@ 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;