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 0F8C7C3DA6E for ; Sat, 17 Dec 2022 00:12:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230317AbiLQAMI (ORCPT ); Fri, 16 Dec 2022 19:12:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44200 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230181AbiLQALY (ORCPT ); Fri, 16 Dec 2022 19:11:24 -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 3CEDB40800; Fri, 16 Dec 2022 16:10:32 -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 CB3E8622C9; Sat, 17 Dec 2022 00:10:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D9BF3C433EF; Sat, 17 Dec 2022 00:10:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671235831; bh=y9bwSUuc+lA1U3NC4hPJWbpqyHp4QqmMJF7rGIqbdi8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z7N7zvdbu6GvkIOJ1Eeyn+JUuUV0XcWHBnoxJygoc0z1Z/JZ3MCjbb6dejfP0ctl2 yuYIyiD/KdX+00xXXDGnyXGf4CEI+dx0eW8J45zcwd3ck3EfStyIlVXugrzqp/KJ/B xLFPXz0pyvOQyM0locaK0FFFCd4O54Ip01VkUXYZy/pzH601WmxyWcXkvbB40e07EU p5mLQqFBY5+kjkYuYDSifXIGaSFoZh6hhyo+b5zqVetSP4Nqxezlye2F7uu4s/OPGq 4jw0m5W8ktEigltY8NKDOm7lN950+auPw2IIc8EXxF2FCDMvxNOqBFEz9zUGLeeEBY sicaDthF//H3g== 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 6.0 5/8] x86/hyperv: Remove unregister syscore call from Hyper-V cleanup Date: Fri, 16 Dec 2022 19:10:09 -0500 Message-Id: <20221217001013.41239-5-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221217001013.41239-1-sashal@kernel.org> References: <20221217001013.41239-1-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 a0165df3c4d8..d03561b2fffe 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -536,8 +536,6 @@ 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); hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, 0); -- 2.35.1