From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751320AbcANIZg (ORCPT ); Thu, 14 Jan 2016 03:25:36 -0500 Received: from www.linutronix.de ([62.245.132.108]:53882 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750734AbcANIZe (ORCPT ); Thu, 14 Jan 2016 03:25:34 -0500 Date: Thu, 14 Jan 2016 09:24:35 +0100 (CET) From: Thomas Gleixner To: Joe Lawrence cc: LKML , Ingo Molnar , Peter Anvin , Jiang Liu , Jeremiah Mahler , Borislav Petkov , andy.shevchenko@gmail.com, Guenter Roeck Subject: Re: [patch 00/14] x86/irq: Plug various vector cleanup races In-Reply-To: <568A9157.9070402@stratus.com> Message-ID: References: <20151231155849.772553760@linutronix.de> <568A9157.9070402@stratus.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 4 Jan 2016, Joe Lawrence wrote: > No issues running the same PCI device removal and stress tests against > the patchset. Thanks for testing! Though there is yet another long standing bug in that area. Fix below. Thanks, tglx 8<-------------------- Subject: x86/irq: Call chip->irq_set_affinity in proper context From: Thomas Gleixner Date: Thu, 14 Jan 2016 08:43:38 +0100 setup_ioapic_dest() calls irqchip->irq_set_affinity() completely unprotected. That's wrong in several aspects: - it triggers a lockdep splat because vector lock is taken with interrupts enabled. - it opens a race window where irq_set_affinity() can be interrupted and the irq chip left in unconsistent state. The proper calling convention is irq descriptor lock held and interrupts disabled. Reported-by: Borislav Petkov Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org --- arch/x86/kernel/apic/io_apic.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -2521,6 +2521,7 @@ void __init setup_ioapic_dest(void) { int pin, ioapic, irq, irq_entry; const struct cpumask *mask; + struct irq_desc *desc; struct irq_data *idata; struct irq_chip *chip; @@ -2536,7 +2537,9 @@ void __init setup_ioapic_dest(void) if (irq < 0 || !mp_init_irq_at_boot(ioapic, irq)) continue; - idata = irq_get_irq_data(irq); + desc = irq_to_desc(irq); + raw_spin_lock_irq(d&desc->lock); + idata = irq_desc_get_irq_data(desc); /* * Honour affinities which have been set in early boot @@ -2550,6 +2553,7 @@ void __init setup_ioapic_dest(void) /* Might be lapic_chip for irq 0 */ if (chip->irq_set_affinity) chip->irq_set_affinity(idata, mask, false); + raw_spin_unlock_irq(d&desc->lock); } } #endif