From: Alex Williamson alex.williamson@redhat.com
stable inclusion from linux-4.19.154 commit f393f4a5fcbc38248a9a261f4cbee8ea5b1296fd
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[ Upstream commit 852b1beecb6ff9326f7ca4bc0fe69ae860ebdb9e ]
The eventfd context is used as our irqbypass token, therefore if an eventfd is re-used, our token is the same. The irqbypass code will return an -EBUSY in this case, but we'll still attempt to unregister the producer, where if that duplicate token still exists, results in removing the wrong object. Clear the token of failed producers so that they harmlessly fall out when unregistered.
Fixes: 6d7425f109d2 ("vfio: Register/unregister irq_bypass_producer") Reported-by: guomin chen guomin_chen@sina.com Tested-by: guomin chen guomin_chen@sina.com Signed-off-by: Alex Williamson alex.williamson@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/vfio/pci/vfio_pci_intrs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c index bdfdd506bc58..c989f777bf77 100644 --- a/drivers/vfio/pci/vfio_pci_intrs.c +++ b/drivers/vfio/pci/vfio_pci_intrs.c @@ -355,11 +355,13 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev, vdev->ctx[vector].producer.token = trigger; vdev->ctx[vector].producer.irq = irq; ret = irq_bypass_register_producer(&vdev->ctx[vector].producer); - if (unlikely(ret)) + if (unlikely(ret)) { dev_info(&pdev->dev, "irq bypass producer (token %p) registration fails: %d\n", vdev->ctx[vector].producer.token, ret);
+ vdev->ctx[vector].producer.token = NULL; + } vdev->ctx[vector].trigger = trigger;
return 0;