Bug 1598773 - Freeze during boot causes by "options nf_conntrack hashsize=2000000" in /etc/modprobe.d
Summary: Freeze during boot causes by "options nf_conntrack hashsize=2000000" in /etc/...
Keywords:
Status: CLOSED WORKSFORME
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 28
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2018-07-06 12:29 UTC by Rolf Fokkens
Modified: 2018-11-03 20:58 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2018-11-03 20:58:54 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)
"Screenshot" showing the kernel stack trace on a laptop (738.24 KB, image/jpeg)
2018-07-06 12:29 UTC, Rolf Fokkens
no flags Details

Description Rolf Fokkens 2018-07-06 12:29:57 UTC
Created attachment 1456995 [details]
"Screenshot" showing the kernel stack trace on a laptop

Description of problem:
After upgrading to Fedora 28, the system boot hangs due to these settings in /etc/modprobe.d/*:
options nf_conntrack hashsize=2000000

Version-Release number of selected component (if applicable):
kernel 4.17.3-200.fc28

How reproducible:
100%, bot on VM's and laptops.

Steps to Reproduce:
1. Install Fedora 27, upgrade to Fedora 28
2. Create a file /etc/modprobe.d/test.conf containing "options nf_conntrack hashsize=2000000"
3. Do a modprobe nf_conntrack
4. Watch the fireworks

Actual results:
Kernel crash

Expected results:
Happy system

Additional info:

[root@test ~]# modprobe -v nf_conntrack
insmod /lib/modules/4.17.3-200.fc28.x86_64/kernel/lib/libcrc32c.ko.xz 
install /sbin/modprobe --ignore-install nf_conntrack $CMDLINE_OPTS && /sbin/sysctl --quiet --pattern 'net[.]netfilter[.]nf_conntrack.*' --system hashsize=2000000 
insmod /lib/modules/4.17.3-200.fc28.x86_64/kernel/net/netfilter/nf_conntrack.ko.xz hashsize=2000000 hashsize=2000000
<CRASH>

The issue seems to be caused by repeating hashsize=2000000 twice. Doing a manual insmod with hashsize=2000000 only once seems to cause no problems.

Comment 1 Rolf Fokkens 2018-07-06 12:32:16 UTC
This is reproducable on VM's, but VM's on oVirt (4.0) crash hard, leaving nu crashdumps.

Comment 2 Laura Abbott 2018-10-01 21:15:45 UTC
We apologize for the inconvenience.  There is a large number of bugs to go through and several of them have gone stale.  Due to this, we are doing a mass bug update across all of the Fedora 28 kernel bugs.
 
Fedora 28 has now been rebased to 4.18.10-300.fc28.  Please test this kernel update (or newer) and let us know if you issue has been resolved or if it is still present with the newer kernel.
 
If you have moved on to Fedora 29, and are still experiencing this issue, please change the version to Fedora 29.
 
If you experience different issues, please open a new bug report for those.

Comment 3 Rolf Fokkens 2018-11-03 20:58:54 UTC
Seems to be solved.


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