Re: [BUG 4.15-rc7] IRQ matrix management errors

From: Keith Busch
Date: Wed Jan 17 2018 - 02:51:50 EST


On Wed, Jan 17, 2018 at 08:34:22AM +0100, Thomas Gleixner wrote:
> Can you trace the matrix allocations from the very beginning or tell me how
> to reproduce. I'd like to figure out why this is happening.

Sure, I'll get the irq_matrix events.

I reproduce this on a machine with 112 CPUs and 3 NVMe controllers. The
first two NVMe want 112 MSI-x vectors, and the last only 31 vectors. The
test runs 'modprobe nvme' and 'modprobe -r nvme' in a loop with 10
second delay between each step. Repro occurs within a few iterations,
sometimes already broken after the initial boot.