irqdomain: Fix disassociation race

commit 3f883c38f5628f46b30bccf090faec054088e262 upstream.

The global irq_domain_mutex is held when mapping interrupts from
non-hierarchical domains but currently not when disposing them.

This specifically means that updates of the domain mapcount is racy
(currently only used for statistics in debugfs).

Make sure to hold the global irq_domain_mutex also when disposing
mappings from non-hierarchical domains.

Fixes: d4467db9776e ("genirq/irqdomain: Add map counter")
Cc: stable@vger.kernel.org      # 4.13
Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>
Tested-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230213104302.17307-3-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index bdc4be333175e32eab9d62b721901a2d4bf35f3f..b4e3e15e05ad896447d00f1776c52dd21ee10d26 100644 (file)
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -509,6 +509,9 @@ void irq_domain_disassociate(struct irq_domain *domain, unsigned int irq)
                return;
 
        hwirq = irq_data->hwirq;
+
+       mutex_lock(&irq_domain_mutex);
+
        irq_set_status_flags(irq, IRQ_NOREQUEST);
 
        /* remove chip and handler */
@@ -528,6 +531,8 @@ void irq_domain_disassociate(struct irq_domain *domain, unsigned int irq)
 
        /* Clear reverse map for this hwirq */
        irq_domain_clear_mapping(domain, hwirq);
+
+       mutex_unlock(&irq_domain_mutex);
 }
 
 static int irq_domain_associate_locked(struct irq_domain *domain, unsigned int virq,