Comment 16 for bug 1842447

I agree with Taher (in https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1842447/comments/15), this bug seems to impact a lot of systems (my colo host was kernel panic restarting about every 75-90 minutes, all weekend). It has a NAT firewall on it (for the hosted VMs), but no Docker/Wireguard, etc. My guess for the 75-90 minutes is that is how long it took to dirty enough memory that the relevant value just happened not to already be 0 (NULL). (Curiously I installed -60 on Thursday last week, and the first issue didn't happen until Friday, so it's been worse over the weekend than the first 24 hours. I enabled kernel.panic=15 after the first issue, to automate recovery, and was *extremely* glad I did so.)

Honestly I'd suggest withdrawing -60 as it's very unstable in a lot of common configurations. And also suggest expediting the release of -62, which AFAICT just contains the one line fix for the bug in -60.

Now it's Monday morning (and thus I can get into the colo if needed), I've upgraded the colo system to the proposed -62 version, and crossing my fingers the system is more stable as a result.

In case it helps others, I found I needed to:

(a) https://wiki.ubuntu.com/Testing/EnableProposed (changing "xenial" to "bionic", for 18.04 LTS, including enabling the low priority pin of bionic-proposed); and

(b) sudo apt-get install linux-generic/bionic-proposed linux-signed-generic/bionic-proposed linux-headers-generic/bionic-proposed

(without at least two of those three, the proposed update metapackages wouldn't install due to conflicts; I'm not sure if linux-signed-generic is needed, but it's still installed, so I chose to keep it in sync.)

That list of packages found by looking for 4.15.0-60 versioned packages that didn't have that version in their package name (ie, to find the generic metapackages).

Ewen

PS: Reboots (due to kernel panic, and kernel.panic=15 sysctl) over the weekend:

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ewen@naosr620:~$ last | grep reboot
reboot system boot 4.15.0-62-generi Mon Sep 9 10:43 still running
reboot system boot 4.15.0-60-generi Mon Sep 9 10:14 - 10:39 (00:25)
reboot system boot 4.15.0-60-generi Mon Sep 9 08:48 - 10:09 (01:21)
reboot system boot 4.15.0-60-generi Mon Sep 9 07:33 - 10:09 (02:36)
reboot system boot 4.15.0-60-generi Mon Sep 9 06:18 - 10:09 (03:51)
reboot system boot 4.15.0-60-generi Mon Sep 9 05:03 - 10:09 (05:06)
reboot system boot 4.15.0-60-generi Mon Sep 9 03:48 - 10:09 (06:21)
reboot system boot 4.15.0-60-generi Mon Sep 9 02:33 - 10:09 (07:36)
reboot system boot 4.15.0-60-generi Mon Sep 9 01:13 - 10:09 (08:56)
reboot system boot 4.15.0-60-generi Sun Sep 8 23:58 - 10:09 (10:11)
reboot system boot 4.15.0-60-generi Sun Sep 8 22:43 - 10:09 (11:26)
reboot system boot 4.15.0-60-generi Sun Sep 8 21:28 - 10:09 (12:41)
reboot system boot 4.15.0-60-generi Sun Sep 8 20:08 - 10:09 (14:01)
reboot system boot 4.15.0-60-generi Sun Sep 8 18:53 - 10:09 (15:16)
reboot system boot 4.15.0-60-generi Sun Sep 8 17:38 - 10:09 (16:31)
reboot system boot 4.15.0-60-generi Sun Sep 8 16:23 - 10:09 (17:46)
reboot system boot 4.15.0-60-generi Sun Sep 8 15:08 - 10:09 (19:01)
reboot system boot 4.15.0-60-generi Sun Sep 8 13:53 - 10:09 (20:16)
reboot system boot 4.15.0-60-generi Sun Sep 8 12:29 - 10:09 (21:40)
reboot system boot 4.15.0-60-generi Sun Sep 8 11:14 - 10:09 (22:55)
reboot system boot 4.15.0-60-generi Sun Sep 8 09:57 - 10:09 (1+00:12)
reboot system boot 4.15.0-60-generi Sun Sep 8 08:43 - 10:09 (1+01:26)
reboot system boot 4.15.0-60-generi Sun Sep 8 07:28 - 10:09 (1+02:41)
reboot system boot 4.15.0-60-generi Sun Sep 8 06:13 - 10:09 (1+03:56)
reboot system boot 4.15.0-60-generi Sun Sep 8 04:54 - 10:09 (1+05:15)
reboot system boot 4.15.0-60-generi Sun Sep 8 03:34 - 10:09 (1+06:35)
reboot system boot 4.15.0-60-generi Sun Sep 8 02:18 - 10:09 (1+07:51)
reboot system boot 4.15.0-60-generi Sun Sep 8 01:03 - 10:09 (1+09:06)
reboot system boot 4.15.0-60-generi Sat Sep 7 23:48 - 10:09 (1+10:21)
reboot system boot 4.15.0-60-generi Sat Sep 7 22:55 - 10:09 (1+11:14)
reboot system boot 4.15.0-60-generi Sat Sep 7 22:34 - 10:09 (1+11:35)
reboot system boot 4.15.0-60-generi Sat Sep 7 21:19 - 10:09 (1+12:50)
reboot system boot 4.15.0-60-generi Sat Sep 7 20:03 - 10:09 (1+14:06)
reboot system boot 4.15.0-60-generi Sat Sep 7 18:48 - 10:09 (1+15:21)
reboot system boot 4.15.0-60-generi Sat Sep 7 17:33 - 10:09 (1+16:36)
reboot system boot 4.15.0-60-generi Sat Sep 7 16:18 - 10:09 (1+17:51)
reboot system boot 4.15.0-60-generi Sat Sep 7 15:03 - 10:09 (1+19:06)
reboot system boot 4.15.0-60-generi Sat Sep 7 13:42 - 10:09 (1+20:27)
reboot system boot 4.15.0-60-generi Sat Sep 7 12:27 - 10:09 (1+21:42)
reboot system boot 4.15.0-60-generi Sat Sep 7 11:12 - 10:09 (1+22:57)
reboot system boot 4.15.0-60-generi Sat Sep 7 10:57 - 10:09 (1+23:12)
reboot system boot 4.15.0-60-generi Sat Sep 7 09:58 - 10:09 (2+00:11)
reboot system boot 4.15.0-60-generi Sat Sep 7 08:43 - 10:09 (2+01:26)
reboot system boot 4.15.0-60-generi Sat Sep 7 07:27 - 10:09 (2+02:42)
reboot system boot 4.15.0-60-generi Sat Sep 7 06:07 - 10:09 (2+04:02)
reboot system boot 4.15.0-60-generi Sat Sep 7 04:52 - 10:09 (2+05:17)
reboot system boot 4.15.0-60-generi Sat Sep 7 03:37 - 10:09 (2+06:32)
reboot system boot 4.15.0-60-generi Sat Sep 7 02:36 - 10:09 (2+07:33)
reboot system boot 4.15.0-60-generi Sat Sep 7 02:07 - 10:09 (2+08:02)
reboot system boot 4.15.0-60-generi Sat Sep 7 01:53 - 10:09 (2+08:16)
reboot system boot 4.15.0-60-generi Fri Sep 6 11:27 - 10:09 (2+22:42)
reboot system boot 4.15.0-60-generi Thu Sep 5 12:11 - 10:09 (3+21:58)
ewen@naosr620:~$
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