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 A49EFC3DA7D for ; Wed, 28 Dec 2022 16:43:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234625AbiL1QnT (ORCPT ); Wed, 28 Dec 2022 11:43:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35546 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235011AbiL1Qmw (ORCPT ); Wed, 28 Dec 2022 11:42:52 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E6641FCD0 for ; Wed, 28 Dec 2022 08:37:07 -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 592CF61585 for ; Wed, 28 Dec 2022 16:37:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6B089C433D2; Wed, 28 Dec 2022 16:37:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672245422; bh=y9bwSUuc+lA1U3NC4hPJWbpqyHp4QqmMJF7rGIqbdi8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u6bFD6q5lgoxM23VxAUiErzHeyi8cj6z3XiNsBOMU2B71jbf6dpY8Kbl99OlTLQLn v1+kxXb3Aiesauq1iP2c9OpTt2kTmtawFzLitqoswhl/xhp334nvdgz0BmTW1va4eh 29RnXotypMcbdiYgNp2bQ6CaaQbu5l2lcTpHq2l0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Gaurav Kohli , Michael Kelley , Wei Liu , Sasha Levin Subject: [PATCH 6.0 0889/1073] x86/hyperv: Remove unregister syscore call from Hyper-V cleanup Date: Wed, 28 Dec 2022 15:41:17 +0100 Message-Id: <20221228144352.174692000@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221228144328.162723588@linuxfoundation.org> References: <20221228144328.162723588@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@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