[dpdk-stable] [dpdk-dev] [PATCH] vfio: fix interrupts race condition

[Thomas Monjalon]

10/07/2019 14:33, David Marchand:
> Populating the eventfd in rte_intr_enable in each request to vfio
> triggers a reconfiguration of the interrupt handler on the kernel side.
> The problem is that rte_intr_enable is often used to re-enable masked
> interrupts from drivers interrupt handlers.
> 
> This reconfiguration leaves a window during which a device could send
> an interrupt and then the kernel logs this (unsolicited from the kernel
> point of view) interrupt:
> [158764.159833] do_IRQ: 9.34 No irq handler for vector
> 
> VFIO api makes it possible to set the fd at setup time.
> Make use of this and then we only need to ask for masking/unmasking
> legacy interrupts and we have nothing to do for MSI/MSIX.
> 
> "rxtx" interrupts are left untouched but are most likely subject to the
> same issue.
> 
> Fixes: 5c782b3928b8 ("vfio: interrupts")
> Cc: stable at dpdk.org
> 
> Reported-at: https://bugzilla.redhat.com/show_bug.cgi?id=1654824
> Signed-off-by: David Marchand <david.marchand at redhat.com>
> Tested-by: Shahed Shaikh <shshaikh at marvell.com>

This is a real bug which should be fixed in this release.
As the patch is quite big and needs a strong validation,
I prefer merging it quickly to give a lot of time before
releasing 19.08-rc2.
The maintainers of all concerned PMDs are Cc.
Please make sure the interrupts are still working well with VFIO.

Applied, thanks