From 36f34c8c63da3e272fd66f91089228c22d2b6e8b Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 31 Dec 2015 16:30:45 +0000 Subject: [PATCH] x86/irq: Validate that irq descriptor is still active In fixup_irqs() we unconditionally dereference the irq chip of an irq descriptor. The descriptor might still be valid, but already cleaned up, i.e. the chip removed. Add a check for this condition. Signed-off-by: Thomas Gleixner Cc: Jiang Liu Cc: Joe Lawrence Cc: Jeremiah Mahler Cc: Borislav Petkov Cc: andy.shevchenko@gmail.com Cc: Guenter Roeck Cc: stable@vger.kernel.org #4.3+ Link: http://lkml.kernel.org/r/20151231160106.236423282@linutronix.de Signed-off-by: Thomas Gleixner --- arch/x86/kernel/irq.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index f8062aaf5df9..c0b58dd1ca04 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -470,6 +470,15 @@ void fixup_irqs(void) } chip = irq_data_get_irq_chip(data); + /* + * The interrupt descriptor might have been cleaned up + * already, but it is not yet removed from the radix tree + */ + if (!chip) { + raw_spin_unlock(&desc->lock); + continue; + } + if (!irqd_can_move_in_process_context(data) && chip->irq_mask) chip->irq_mask(data); -- 2.20.1