Patch "genirq/msi: Fix populating multiple interrupts" has been added to the 4.13-stable tree

This is a note to let you know that I've just added the patch titled

genirq/msi: Fix populating multiple interrupts

to the 4.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
genirq-msi-fix-populating-multiple-interrupts.patch
and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: John Keeping <[email protected]>
Date: Wed, 6 Sep 2017 10:35:40 +0100
Subject: genirq/msi: Fix populating multiple interrupts

From: John Keeping <[email protected]>

commit 596a7a1d0989c621c3ae49be73a1d1f9de22eb5a upstream.

On allocating the interrupts routed via a wire-to-MSI bridge, the allocator iterates over the MSI descriptors to build the hierarchy, but fails to use the descriptor interrupt number, and instead uses the base number, generating the wrong IRQ domain mappings.

The fix is to use the MSI descriptor interrupt number when setting up the interrupt instead of the base interrupt for the allocation range.

The only saving grace is that although the MSI descriptors are allocated in bulk, the wired interrupts are only allocated one by one (so desc->irq == virq) and the bug went unnoticed so far.

---
 kernel/irq/msi.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

@@ -315,11 +315,12 @@ int msi_domain_populate_irqs(struct irq_
 
 		ops->set_desc(arg, desc);
 		/* Assumes the domain mutex is held! */
-		ret = irq_domain_alloc_irqs_hierarchy(domain, virq, 1, arg);
+		ret = irq_domain_alloc_irqs_hierarchy(domain, desc->irq, 1,
+						      arg);
 		if (ret)
 			break;
 
-		irq_set_msi_desc_off(virq, 0, desc);
+		irq_set_msi_desc_off(desc->irq, 0, desc);
 	}
 
 	if (ret) {

Patches currently in stable-queue which might be from [email protected] are

queue-4.13/genirq-msi-fix-populating-multiple-interrupts.patch