This is a note to let you know that I've just added the patch titled
vfio/pci: call irq_bypass_unregister_producer() before freeing irq
to the 4.4-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:
vfio-pci-call-irq_bypass_unregister_producer-before-freeing-irq.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d567fb8819162099035e546b11a736e29c2af0ea Mon Sep 17 00:00:00 2001
From: Jiang Yi <giangyi@xxxxxxxxxx>
Date: Wed, 27 Nov 2019 17:49:10 +0100
Subject: vfio/pci: call irq_bypass_unregister_producer() before freeing irq
From: Jiang Yi <giangyi@xxxxxxxxxx>
commit d567fb8819162099035e546b11a736e29c2af0ea upstream.
Since irq_bypass_register_producer() is called after request_irq(), we
should do tear-down in reverse order: irq_bypass_unregister_producer()
then free_irq().
Specifically free_irq() may release resources required by the
irqbypass del_producer() callback. Notably an example provided by
Marc Zyngier on arm64 with GICv4 that he indicates has the potential
to wedge the hardware:
free_irq(irq)
__free_irq(irq)
irq_domain_deactivate_irq(irq)
its_irq_domain_deactivate()
[unmap the VLPI from the ITS]
kvm_arch_irq_bypass_del_producer(cons, prod)
kvm_vgic_v4_unset_forwarding(kvm, irq, ...)
its_unmap_vlpi(irq)
[Unmap the VLPI from the ITS (again), remap the original LPI]
Signed-off-by: Jiang Yi <giangyi@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v4.4+
Fixes: 6d7425f109d26 ("vfio: Register/unregister irq_bypass_producer")
Link: https://lore.kernel.org/kvm/20191127164910.15888-1-giangyi@xxxxxxxxxx
Reviewed-by: Marc Zyngier <maz@xxxxxxxxxx>
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
[aw: commit log]
Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/vfio/pci/vfio_pci_intrs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -318,8 +318,8 @@ static int vfio_msi_set_vector_signal(st
return -EINVAL;
if (vdev->ctx[vector].trigger) {
- free_irq(irq, vdev->ctx[vector].trigger);
irq_bypass_unregister_producer(&vdev->ctx[vector].producer);
+ free_irq(irq, vdev->ctx[vector].trigger);
kfree(vdev->ctx[vector].name);
eventfd_ctx_put(vdev->ctx[vector].trigger);
vdev->ctx[vector].trigger = NULL;
Patches currently in stable-queue which might be from giangyi@xxxxxxxxxx are
queue-4.4/vfio-pci-call-irq_bypass_unregister_producer-before-freeing-irq.patch
