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 421F1C3DA6E for ; Sat, 17 Dec 2022 00:13:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230434AbiLQANr (ORCPT ); Fri, 16 Dec 2022 19:13:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44160 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230293AbiLQAMz (ORCPT ); Fri, 16 Dec 2022 19:12:55 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72F844083B; Fri, 16 Dec 2022 16:11:14 -0800 (PST) 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 D153B622D6; Sat, 17 Dec 2022 00:11:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DACA0C433F1; Sat, 17 Dec 2022 00:11:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671235873; bh=mqZchY+OtGrBo6CJuxAM/N2nwSMXzb7e52XNewtdEW0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MSTI6crwh7q8wlx6A6WAq7Ig/bwuKbuD9G79YDuZZDao/4q45YiLyhcP4WD0Rw0pz xGgwpjzx8f+QKp9Bo3/ug4PmiUYmUqpwf81VsAuonZwj3EYvuDAPVjCuPFhH98kkCX oLZ4vHNkjLSLrsByZ2WXnegOrKlMwHSJ4OwKOzXVJJb0CSvXJg5mSI2CZcfTTN0skc g8LGix45z8eQFo+88imJ+fQlzdngOrnJTlhpeISqXRTxzCAFtkHjb+Z52T0AtSqvNx xyJ/mB7wmkFXw3HkBoNAUH0z60sLgwO5bXUX7S0slmpmV/GPVCKR1+aiJe46nYos2S wpl4z8wiCYAKQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Gaurav Kohli , Michael Kelley , Wei Liu , Sasha Levin , kys@microsoft.com, haiyangz@microsoft.com, decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, linux-hyperv@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 4/5] x86/hyperv: Remove unregister syscore call from Hyper-V cleanup Date: Fri, 16 Dec 2022 19:10:56 -0500 Message-Id: <20221217001058.41426-4-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221217001058.41426-1-sashal@kernel.org> References: <20221217001058.41426-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org From: Gaurav Kohli [ Upstream commit 32c97d980e2eef25465d453f2956a9ca68926a3c ] Hyper-V cleanup code comes under panic path where preemption and irq is already disabled. So calling of unregister_syscore_ops might schedule out the thread even for the case where mutex lock is free. hyperv_cleanup unregister_syscore_ops mutex_lock(&syscore_ops_lock) might_sleep Here might_sleep might schedule out this thread, where voluntary preemption config is on and this thread will never comes back. And also this was added earlier to maintain the symmetry which is not required as this can comes during crash shutdown path only. To prevent the same, removing unregister_syscore_ops function call. Signed-off-by: Gaurav Kohli Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1669443291-2575-1-git-send-email-gauravkohli@linux.microsoft.com Signed-off-by: Wei Liu Signed-off-by: Sasha Levin --- arch/x86/hyperv/hv_init.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 01860c0d324d..70fd21ebb9d5 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -453,8 +453,6 @@ void hyperv_cleanup(void) { union hv_x64_msr_hypercall_contents hypercall_msr; - unregister_syscore_ops(&hv_syscore_ops); - /* Reset our OS id */ wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); -- 2.35.1