From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751827AbeAPLUW (ORCPT + 1 other); Tue, 16 Jan 2018 06:20:22 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:42497 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751434AbeAPLUV (ORCPT ); Tue, 16 Jan 2018 06:20:21 -0500 Date: Tue, 16 Jan 2018 12:20:18 +0100 (CET) From: Thomas Gleixner To: Keith Busch cc: LKML Subject: Re: [BUG 4.15-rc7] IRQ matrix management errors In-Reply-To: Message-ID: References: <20180115025759.GG13580@localhost.localdomain> <20180115030255.GA13921@localhost.localdomain> <20180116061641.GB32639@localhost.localdomain> <20180116071145.GA5643@localhost.localdomain> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Tue, 16 Jan 2018, Thomas Gleixner wrote: > On Tue, 16 Jan 2018, Keith Busch wrote: > > > This is all way over my head, but the part that obviously shows > > something's gone wrong: > > > > kworker/u674:3-1421 [028] d... 335.307051: irq_matrix_reserve_managed: bit=56 cpu=0 online=1 avl=86 alloc=116 managed=3 online_maps=112 global_avl=22084, global_rsvd=157, total_alloc=570 > > kworker/u674:3-1421 [028] d... 335.307053: irq_matrix_remove_managed: bit=56 cpu=0 online=1 avl=87 alloc=116 managed=2 online_maps=112 global_avl=22085, global_rsvd=157, total_alloc=570 > > kworker/u674:3-1421 [028] .... 335.307054: vector_reserve_managed: irq=45 ret=-28 > > kworker/u674:3-1421 [028] .... 335.307054: vector_setup: irq=45 is_legacy=0 ret=-28 > > kworker/u674:3-1421 [028] d... 335.307055: vector_teardown: irq=45 is_managed=1 has_reserved=0 > > > > Which leads me to x86_vector_alloc_irqs goto error: > > > > error: > > x86_vector_free_irqs(domain, virq, i + 1); > > > > The last parameter looks weird. It's the nr_irqs, and since we failed and > > bailed, I would think we'd need to subtract 1 rather than add 1. Adding > > 1 would doublely remove the failed one, and remove the next one that > > was never setup, right? > > Right. That's fishy. Let me stare at it. What we want is s/i + 1/i/ That's correct because x86_vector_free_irqs() does: for (i = 0; i < nr; i++) .... So if we fail at the first irq, then the loop will do nothing. Failing on the second will free the first .... Fix below. Thanks, tglx 8<---------------------- diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c index f8b03bb8e725..3cc471beb50b 100644 --- a/arch/x86/kernel/apic/vector.c +++ b/arch/x86/kernel/apic/vector.c @@ -542,14 +542,17 @@ static int x86_vector_alloc_irqs(struct irq_domain *domain, unsigned int virq, err = assign_irq_vector_policy(irqd, info); trace_vector_setup(virq + i, false, err); - if (err) + if (err) { + irqd->chip_data = NULL; + free_apic_chip_data(apicd); goto error; + } } return 0; error: - x86_vector_free_irqs(domain, virq, i + 1); + x86_vector_free_irqs(domain, virq, i); return err; }