Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932158AbbHFKCw (ORCPT ); Thu, 6 Aug 2015 06:02:52 -0400 Received: from smtp.citrix.com ([66.165.176.89]:24730 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753368AbbHFKCu (ORCPT ); Thu, 6 Aug 2015 06:02:50 -0400 X-IronPort-AV: E=Sophos;i="5.15,622,1432598400"; d="scan'208";a="288660661" Message-ID: <55C330C7.6050204@citrix.com> Date: Thu, 6 Aug 2015 11:02:47 +0100 From: David Vrabel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.7.0 MIME-Version: 1.0 To: "Jason A. Donenfeld" , David Vrabel CC: , Paul McKenney , , Subject: Re: [Xen-devel] printk from softirq on xen: hard lockup References: <55C0F291.7060806@citrix.com> In-Reply-To: Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1093 Lines: 28 On 05/08/15 00:01, Jason A. Donenfeld wrote: > Hey David, > > Sorry for the premature response on my phone earlier. Real reply follows. >>> rcu_read_lock, when using Xen PV. Relevant excerpts of the >> ^^ PV guest? > > Yes. The lockup occurs on a PV guest. Nothing special at all about the > configuration. Vanilla upstream 4.1.3 kernel. > >>> __xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56 >>> 56 while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY) >> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ => HVM guest >> >> Which is it? > > That's odd. It's a PV guest, not an HVM nor PVH guest. Linux PV guests must use the "Xen PV" APIC driver. You need to investigate why your PV guest is not using this (although I'm surprised it works at all with the wrong one). David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/