genirq/msi: Check for the presence of an irq domain when validating msi_ctrl

For architectures such as s390 and powerpc that do not use
irq domains for MSIs, dev->msi.domain is always NULL, so
the per-device, per-bus MSI domain is also guaranteed to
be NULL.

So checking one without checking the other is bound to result
in a splat, followed by a memory leak as we don't free the MSI
descriptors.

Add the missing check.

Reported-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/e570e70d-19bc-101b-0481-ff9a3cab3504@linux.ibm.com

diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index bd4d4dd..e843604 100644 (file)
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -165,7 +165,8 @@ static bool msi_ctrl_valid(struct device *dev, struct msi_ctrl *ctrl)
        unsigned int hwsize;
 
        if (WARN_ON_ONCE(ctrl->domid >= MSI_MAX_DEVICE_IRQDOMAINS ||
-                        !dev->msi.data->__domains[ctrl->domid].domain))
+                        (dev->msi.domain &&
+                         !dev->msi.data->__domains[ctrl->domid].domain)))
                return false;
 
        hwsize = msi_domain_get_hwsize(dev, ctrl->domid);