Ubuntu
zfs-linux package

Need patch for post 5.5 low-latency kernels

Bug #1866730 reported by satmandu
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
zfs-linux (Ubuntu)
Fix Released
Medium
Colin Ian King

Bug Description

CONFIG_PREEMPT_RCU=y enabled post 5.4.x kernels have __rcu_read_lock exposed as GPL-ONLY, which breaks zfs compilation on kernels with that enabled. (Ubuntu low-latency kernels have that enabled IIRC.)

The patch for the .8 series implementing this inside zfs to circumvent this issue is here: https://github.com/openzfs/zfs/commit/2fcab8795c7c493845bfa277d44bc443802000b8

This is from this comment in the relevant issue:

https://github.com/openzfs/zfs/issues/9745#issuecomment-592617605

Colin Ian King (colin-king)
Changed in zfs-linux (Ubuntu):
assignee: nobody → Colin Ian King (colin-king)
importance: Undecided → Medium
status: New → In Progress
Revision history for this message
Colin Ian King (colin-king) wrote :

Thanks for the update on this compat fix.

I've tested this on:

upstream 5.6-rc5 lowlatency + generic
upstream 5.5 lowlatency + generic
ubuntu 5.4.0-18

Colin Ian King (colin-king)
Changed in zfs-linux (Ubuntu):
status: In Progress → Fix Committed
Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package zfs-linux - 0.8.3-1ubuntu8

---------------
zfs-linux (0.8.3-1ubuntu8) focal; urgency=medium

  * Add 5.5 low-latency compat fixe (LP: #1866730)
    - Apply backported upstream zfs fix for Linux 5.5 compat fix
    - 2fcab8795c7c ("Linux 5.5 compat: blkg_tryget()")

 -- Colin Ian King <email address hidden> Tue, 10 Mar 2020 09:52:11 +0000

Changed in zfs-linux (Ubuntu):
status: Fix Committed → Fix Released
Revision history for this message
satmandu (satadru-umich) wrote :

FYI this patch is part of the just released 0.8.4 in https://github.com/openzfs/zfs/tree/zfs-0.8-release as per the patch pull request: https://github.com/openzfs/zfs/pull/10209

Revision history for this message
Colin Ian King (colin-king) wrote :

Is that FYI just for reference or is it indicating that further patches need applying?

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