From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman Subject: [PATCH 4.4 322/342] x86/irq: Call chip->irq_set_affinity in proper context To: Cc: Greg Kroah-Hartman , , Thomas Gleixner , Jiang Liu , Jeremiah Mahler , , Guenter Roeck , Joe Lawrence Message-Id: <20160301234538.275401898@linuxfoundation.org> In-Reply-To: <20160301234527.990448862@linuxfoundation.org> References: <20160301234527.990448862@linuxfoundation.org> Date: Tue, 01 Mar 2016 23:55:39 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner commit e23b257c293ce4bcc8cabb2aa3097b6ed8a8261a upstream. setup_ioapic_dest() calls irqchip->irq_set_affinity() completely unprotected. That's wrong in several aspects: - it opens a race window where irq_set_affinity() can be interrupted and the irq chip left in unconsistent state. - it triggers a lockdep splat when we fix the vector race for 4.3+ because vector lock is taken with interrupts enabled. The proper calling convention is irq descriptor lock held and interrupts disabled. Reported-and-tested-by: Borislav Petkov Signed-off-by: Thomas Gleixner Cc: Jiang Liu Cc: Jeremiah Mahler Cc: andy.shevchenko@gmail.com Cc: Guenter Roeck Cc: Joe Lawrence Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1601140919420.3575@nanos Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- 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(&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(&desc->lock); } } #endif