User reports a hang on 18.04 LTS(4.15.18) under a heavy I/O load

Bug #1805693 reported by Jay Vosburgh on 2018-11-28
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
High
Unassigned
Bionic
High
Unassigned

Bug Description

User reports a hang under heavy I/O:

The IO hang problem on our cloud is caused by IO hang in block-wbt wbt_wait.
The fix commit id is 2887e41b910bb14fd847cf01ab7a5993db989d88. It is a block write buffer throttle queue lock contention and thundering herd issue in wbt_wait()

We can recreate the problem easily by running concurrent IO from multiple VMs with sequential write. We can provide fio workload as needed for recreate.

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1805693

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

Changed in linux (Ubuntu):
status: New → Incomplete
tags: added: bionic
Changed in linux (Ubuntu):
importance: Undecided → High
status: Incomplete → Triaged
Changed in linux (Ubuntu Bionic):
status: New → Triaged
importance: Undecided → High
tags: added: kernel-da-key
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