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 EDEDEC4708E for ; Sat, 17 Dec 2022 00:10:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230009AbiLQAKJ (ORCPT ); Fri, 16 Dec 2022 19:10:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229637AbiLQAKE (ORCPT ); Fri, 16 Dec 2022 19:10:04 -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 E3B7973325; Fri, 16 Dec 2022 16:10:03 -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 77F2A622CB; Sat, 17 Dec 2022 00:10:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 64860C433F0; Sat, 17 Dec 2022 00:10:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671235802; bh=cbQ8SyZFREV8vFF9bRS676PytjnbqBvZbE1b8YYjSf8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KGVT1lR1BSEPI+IT1MXvZWsKzQD/5/VCMxoJHsoTgvmhcTi+6upkcUaJjVyTJtaQk Zw9293ccCV/DqhhsCUMLb3OMNLShFzGyD1edtp9e1w7+xnDbOFSdUxuUSyJFg/Phti HDFvkNiBO0KLsZLG2DUrTDjy2/5Ipcv4ntzatt5yABulm6xHzFYrq5qNTlrdSyyo+i tNVNcJP3f4NzROaYWrcMamzh4CeL8ysnBYHZRn6Po9B2sVOEVPcWdYlli1lr2983oN XFIqJtAxWsRA0qNUKIkF+702zM2MrLmaaamBdT/b0oXgj4zh5OSXihcsLnG2bqM+E9 ViMl1a741De0A== 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 6.1 5/9] x86/hyperv: Remove unregister syscore call from Hyper-V cleanup Date: Fri, 16 Dec 2022 19:09:32 -0500 Message-Id: <20221217000937.41115-5-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221217000937.41115-1-sashal@kernel.org> References: <20221217000937.41115-1-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 a269049a43ce..85863b9c9e68 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -535,8 +535,6 @@ void hyperv_cleanup(void) union hv_x64_msr_hypercall_contents hypercall_msr; union hv_reference_tsc_msr tsc_msr; - unregister_syscore_ops(&hv_syscore_ops); - /* Reset our OS id */ wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, 0); -- 2.35.1