From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1874556-1527163096-2-9492969032473453682 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, MAILING_LIST_MULTI -1, RCVD_IN_DNSWL_HI -5, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1527163095; b=bXTRYrvQzPILf9+D6wh8IEmh44kDRzwwDicDekq9n65o9joAoE nu5S8U5DL7Qw+kDPLs1wViot1dP5396LprWVXry4slKE57+g+KA7KbWG5tFzOPG6 rAUj2YjUsx+9yyUAisDGm2WFEiygrVtSNirP5ejzz4RZrvIgsOn6zU1CACeDkeiK l+I/FzJiaPZ3vSjSRcoMiuFlALEb7dTCQEr4EvX5W/1ykEZqso8GoPWYAOtoq6y4 eks1aP4eKyx1z2ruthYjjX6+zSFT4WnKfyGRZmw7m4Jfs5ik1BSg/OWdKvozVdmb o3W0muEQ5ZAbkrZ/0aHu6kQiUsmjRpnOaenw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=fm2; t=1527163095; bh=ebp+fBdd9hA4rSax4+rb1j1Dgj8I8U DIWwKebeAlAoo=; b=PrJULqlvdTysqHRymDSzHy14QbcGR92e5frPGcVR9GMplv Sw9eHhPaNEQUSMXtTqLhUjZBpcDXGM+tKK2rzBFme9b9wQCVUH/AyU9I3/iXXKL+ +JG2EOBy52BWpzdct8XywZtXntufWU7JSBlfPlyQC+UNizH5cv5timw4G/wNtyey mw6fzrFXZYX7iUTDZgUvAKrAzfq+dhe8fTM4IRY5WS8GEMl5QOQwKdDBaERUSYab Rf0vM+/v1RY0misn0C3lJi+Y0NHsvfdsSyh+JhmCDTZLn8xbQCsIiduz/ddtxRJG uu/DFclBlqAdi6aNkoKSK1Gc/8OcryEJEjB5CPuw== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=kernel.org header.i=@kernel.org header.b=biXDH3OP x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=default; dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=kernel.org header.i=@kernel.org header.b=biXDH3OP x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=default; dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfCABKd33EYcLIWwzHKJ8r7iUsi9wQKeWc8t8qWuJXoC1CNd2ws4D6irlXeHCimTX4icWSbaClrZt6KFhY9/E2Za8Zii1W8FoSzMjXQvEUKaP3xM+xtVW eGImVoZiBdnmkt/GfRzhgZOFAJPPxiKD1v1VjBJbacC6x7xxXsTWr2rr5RQZvjCz3aPtts4WIoyDHP2zhnauorI8Zqg+T689xW191qjPVFTH/vUaQLNbUgl/ X-CM-Analysis: v=2.3 cv=JLoVTfCb c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=IkcTkHD0fZMA:10 a=VUJBJC2UJ8kA:10 a=yMhMjlubAAAA:8 a=JfrnYn6hAAAA:8 a=pGLkceISAAAA:8 a=VwQbUJbxAAAA:8 a=ag1SF4gXAAAA:8 a=Z4Rwk6OoAAAA:8 a=1XWaLZrsAAAA:8 a=UqCG9HQmAAAA:8 a=iyhmCyC8aMnclnDsskkA:9 a=QEXdDO2ut3YA:10 a=1CNFftbPRP8L7MoqJWF3:22 a=AjGcO6oz07-iQ99wixmX:22 a=Yupwre4RP9_Eg_Bd0iYG:22 a=HkZW87K1Qel5hWWM3VKY:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S969479AbeEXL6M (ORCPT ); Thu, 24 May 2018 07:58:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:56612 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966786AbeEXJp0 (ORCPT ); Thu, 24 May 2018 05:45:26 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dexuan Cui , Thomas Gleixner , Josh Poulson , "Michael Kelley (EOSG)" , Peter Zijlstra , Frederic Weisbecker , Rakib Mullick , Jork Loeser , Andrew Morton , KY Srinivasan , Linus Torvalds , Alexey Dobriyan , Dmitry Vyukov Subject: [PATCH 4.4 64/92] tick/broadcast: Use for_each_cpu() specially on UP kernels Date: Thu, 24 May 2018 11:38:41 +0200 Message-Id: <20180524093205.462096885@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180524093159.286472249@linuxfoundation.org> References: <20180524093159.286472249@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dexuan Cui commit 5596fe34495cf0f645f417eb928ef224df3e3cb4 upstream. for_each_cpu() unintuitively reports CPU0 as set independent of the actual cpumask content on UP kernels. This causes an unexpected PIT interrupt storm on a UP kernel running in an SMP virtual machine on Hyper-V, and as a result, the virtual machine can suffer from a strange random delay of 1~20 minutes during boot-up, and sometimes it can hang forever. Protect if by checking whether the cpumask is empty before entering the for_each_cpu() loop. [ tglx: Use !IS_ENABLED(CONFIG_SMP) instead of #ifdeffery ] Signed-off-by: Dexuan Cui Signed-off-by: Thomas Gleixner Cc: Josh Poulson Cc: "Michael Kelley (EOSG)" Cc: Peter Zijlstra Cc: Frederic Weisbecker Cc: stable@vger.kernel.org Cc: Rakib Mullick Cc: Jork Loeser Cc: Greg Kroah-Hartman Cc: Andrew Morton Cc: KY Srinivasan Cc: Linus Torvalds Cc: Alexey Dobriyan Cc: Dmitry Vyukov Link: https://lkml.kernel.org/r/KL1P15301MB000678289FE55BA365B3279ABF990@KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM Link: https://lkml.kernel.org/r/KL1P15301MB0006FA63BC22BEB64902EAA0BF930@KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM Signed-off-by: Greg Kroah-Hartman --- kernel/time/tick-broadcast.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -610,6 +610,14 @@ static void tick_handle_oneshot_broadcas now = ktime_get(); /* Find all expired events */ for_each_cpu(cpu, tick_broadcast_oneshot_mask) { + /* + * Required for !SMP because for_each_cpu() reports + * unconditionally CPU0 as set on UP kernels. + */ + if (!IS_ENABLED(CONFIG_SMP) && + cpumask_empty(tick_broadcast_oneshot_mask)) + break; + td = &per_cpu(tick_cpu_device, cpu); if (td->evtdev->next_event.tv64 <= now.tv64) { cpumask_set_cpu(cpu, tmpmask);