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 9715BC4167E for ; Tue, 12 Apr 2022 06:46:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350920AbiDLGsS (ORCPT ); Tue, 12 Apr 2022 02:48:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42838 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351128AbiDLGoE (ORCPT ); Tue, 12 Apr 2022 02:44:04 -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 147E5396A2; Mon, 11 Apr 2022 23:37:28 -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 743DD618FF; Tue, 12 Apr 2022 06:37:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 86B0DC385A1; Tue, 12 Apr 2022 06:37:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649745447; bh=11xosoxBbwNZ3oww6FL7EDRNJy+45l+sLxuj6BTSsRA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rILycL4yoO5mDcrBkKsTsRx6ac0LUjIQQi66qMehxuRHRpH5mmOuH0UPWhmxc19k0 JzImq9mkgtZfULgRD5D5C0xmex6Wgcz0uHX+O+Xqhulm/Uk3XtXdpytXnUPWbaDLXp /TBhd+M7V8BeyVYPH7x6n99L0L3wyM+/IpSWei30= 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 5.10 099/171] Drivers: hv: vmbus: Fix potential crash on module unload Date: Tue, 12 Apr 2022 08:29:50 +0200 Message-Id: <20220412062930.748485360@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412062927.870347203@linuxfoundation.org> References: <20220412062927.870347203@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 362da2a83b47..b9ac357e465d 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -2673,10 +2673,15 @@ 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