Comment 4 for bug 1807393

The bug was verified in Xenial kernel 4.4.0-142.168 available in -proposed.

I'm running in an AWS 2-cpu instance, which exhibits the issue if we run a small reproducer script (a loop that basically changes IRQ affinity for the NVMe MSIs/legacy interrupt among the CPUs and performs a 4K write to the device + sync):

$ uptime
 17:42:11 up 4:00, 2 users, load average: 0.19, 0.14, 0.08

$ uname -rmv
4.4.0-142-generic #168-Ubuntu SMP Wed Jan 16 21:00:45 UTC 2019 x86_64

$ dmesg
[ 2218.252634] nvme 0000:00:04.0: I/O 6 QID 2 timeout, completion polled
[ 2451.245962] nvme 0000:00:04.0: I/O 22 QID 2 timeout, completion polled
[ 6672.249406] nvme 0000:00:04.0: I/O 3 QID 1 timeout, completion polled
[ 8425.253863] nvme 0000:00:04.0: I/O 28 QID 2 timeout, completion polled

<notice I've cleared the dmesg after the boot>

Cheers,

Guilherme