genirq/debugfs: Add missing sanity checks to interrupt injection

Interrupts cannot be injected when the interrupt is not activated and when
a replay is already in progress.

Fixes: 536e2e34bd00 ("genirq/debugfs: Triggering of interrupts from userspace")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20200306130623.500019114@linutronix.de

diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c
index a949bd39e343e936b816531feb66c2ed0cd52027..d44c8fd1760931bdd55e536fc4db153b21df8ae7 100644 (file)
--- a/kernel/irq/debugfs.c
+++ b/kernel/irq/debugfs.c
@@ -206,8 +206,15 @@ static ssize_t irq_debug_write(struct file *file, const char __user *user_buf,
                chip_bus_lock(desc);
                raw_spin_lock_irqsave(&desc->lock, flags);
 
-               if (irq_settings_is_level(desc) || desc->istate & IRQS_NMI) {
-                       /* Can't do level nor NMIs, sorry */
+               /*
+                * Don't allow injection when the interrupt is:
+                *  - Level or NMI type
+                *  - not activated
+                *  - replaying already
+                */
+               if (irq_settings_is_level(desc) ||
+                   !irqd_is_activated(&desc->irq_data) ||
+                   (desc->istate & (IRQS_NMI | IRQS_REPLAY))) {
                        err = -EINVAL;
                } else {
                        desc->istate |= IRQS_PENDING;