Comment 13 for bug 1926081

Guilherme, thank you for your kind words :)

I have been trying to reproduce this bug on several other systems that I have access to in our cloud account, but I have been unable to reproduce it on a VM (either with SAN or local SSD storage). The main set of servers where this has been seen by us are bare-metal servers with a RAID card backed by SSDs - it's possible that a combination of the resources available on the machine (CPU, RAM, disk IO) cause this bug to be more reproducible with my basic testcase.

I have taken a server out of production and rebooted it into the 4.15 kernel (4.15.0-141-generic) where the issue is able to be seen.

I confirmed my testcase still reproduces the issue here, and it does - nr_writeback is currently stuck at 2641 after one iteration.

I have supplied the apport collected information from that server, which is now attached to this issue.

This is my first bug report on Launchpad, so I am as yet unfamiliar with the process of testing the potential patches I need. Are you suggesting that I follow the process to rebuild the kernel (https://wiki.ubuntu.com/Kernel/BuildYourOwnKernel) including the patches you have mentioned?

Assuming that is the correct course of action I'll attempt to follow the instructions and do that, and report back.