4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Thomas Gleixner <[email protected]> commit 36f34c8c63da3e272fd66f91089228c22d2b6e8b upstream. 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 <[email protected]> Cc: Jiang Liu <[email protected]> Cc: Joe Lawrence <[email protected]> Cc: Jeremiah Mahler <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: [email protected] Cc: Guenter Roeck <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> 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);
