On Fri, Mar 06, 2026 at 02:19:09PM +0000, Praveen Kannoju wrote:

quoted

On Thu, Mar 05, 2026 at 05:08:52PM +0000, Praveen Kannoju wrote:

quoted

   Regardless of the underlying causes, which may include IRQ loss
   or EQ re-arming failure, the TX queue becomes stuck, and the
   timeout handler is only triggered once the queue is declared
   full. In scenarios where only specialized packets, such as
   heartbeat packets, are sent through the queue, it takes
   significantly longer for the queue to fill and be identified as
   stuck. A proven solution for this issue is polling the EQ
   immediately after the corresponding IRQ migration, which allows
   for earlier recovery and prevents the transmission queue from
   becoming stuck.

I undersand all of this, but for upstreaming we want the root cause, not
bodges like this.

There is no reason to do what this patch does, the IRQ system is not supposed
to loose interrupts on migration, if that is happening on your systems it is a
serious bug that must be root caused.

Thank you, Jason.
We'll evaluate more on it.

If this is in a VM running under qemu - qemu does Lots Of Stuff
whenever a MSI-X is changed and that stuff has been buggy before and
resulted in lost things.

If it is bare metal, I'm shocked. Maybe an IOMMU driver bug in the
interrupt remapping?

Jason