Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756009Ab3EJOWA (ORCPT ); Fri, 10 May 2013 10:22:00 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:57261 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755601Ab3EJOV4 (ORCPT ); Fri, 10 May 2013 10:21:56 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Konrad Rzeszutek Wilk" Date: Fri, 10 May 2013 14:39:41 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [037/118] xen/time: Fix kasprintf splat when allocating timer%d IRQ line. In-Reply-To: X-SA-Exim-Connect-IP: 2001:470:1f08:1539:d51a:8785:aa0a:cebe X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2707 Lines: 77 3.2.45-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Konrad Rzeszutek Wilk commit 7918c92ae9638eb8a6ec18e2b4a0de84557cccc8 upstream. When we online the CPU, we get this splat: smpboot: Booting Node 0 Processor 1 APIC 0x2 installing Xen timer for CPU 1 BUG: sleeping function called from invalid context at /home/konrad/ssd/konrad/linux/mm/slab.c:3179 in_atomic(): 1, irqs_disabled(): 0, pid: 0, name: swapper/1 Pid: 0, comm: swapper/1 Not tainted 3.9.0-rc6upstream-00001-g3884fad #1 Call Trace: [] __might_sleep+0xda/0x100 [] __kmalloc_track_caller+0x1e7/0x2c0 [] ? kasprintf+0x38/0x40 [] kvasprintf+0x5b/0x90 [] kasprintf+0x38/0x40 [] xen_setup_timer+0x30/0xb0 [] xen_hvm_setup_cpu_clockevents+0x1f/0x30 [] start_secondary+0x19c/0x1a8 The solution to that is use kasprintf in the CPU hotplug path that 'online's the CPU. That is, do it in in xen_hvm_cpu_notify, and remove the call to in xen_hvm_setup_cpu_clockevents. Unfortunatly the later is not a good idea as the bootup path does not use xen_hvm_cpu_notify so we would end up never allocating timer%d interrupt lines when booting. As such add the check for atomic() to continue. Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Ben Hutchings --- arch/x86/xen/enlighten.c | 5 ++++- arch/x86/xen/time.c | 6 +++++- 2 files changed, 9 insertions(+), 2 deletions(-) --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1391,8 +1391,11 @@ static int __cpuinit xen_hvm_cpu_notify( switch (action) { case CPU_UP_PREPARE: xen_vcpu_setup(cpu); - if (xen_have_vector_callback) + if (xen_have_vector_callback) { xen_init_lock_cpu(cpu); + if (xen_feature(XENFEAT_hvm_safe_pvclock)) + xen_setup_timer(cpu); + } break; default: break; --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -497,7 +497,11 @@ static void xen_hvm_setup_cpu_clockevent { int cpu = smp_processor_id(); xen_setup_runstate_info(cpu); - xen_setup_timer(cpu); + /* + * xen_setup_timer(cpu) - snprintf is bad in atomic context. Hence + * doing it xen_hvm_cpu_notify (which gets called by smp_init during + * early bootup and also during CPU hotplug events). + */ xen_setup_cpu_clockevents(); } -- 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/