Bug 78945 – ARP Problem with Kernel 2.4.28 (gentoo-sources-2.4.28-r5 and also hardened-sources-2.4.28-r2)

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Horst Prote 2005-01-21 06:18:16 UTC]

After upgrading to kernel 2.4.28 I noticed that some NFS mounts failed at reboot:

   * Mounting network filesystems ...                                     [ !! ]
  mount: RPC: Unable to receive; errno = No route to host

which turns out to be a problem with arp: There are two ARP entries for the NFS server. One is correct, and one says "(incomplete)" in the HWaddress column of
"arp -v". Strangely this only occured to the second NFS mount entry in
/etc/fstab and never to the first (I only have two NFS mounts in /etc/fstab 
and didn't try it with three or more).

When I log in to the NFS client and ping the NFS server the arp-cache gets
fixed up and I can mount the NFS filesystem by hand.

Reproducible: Sometimes
Steps to Reproduce:
1. Build 2.4.28 Kernel
2. Have at least two NFS mounts in /etc/fstab and netmount in default run-level
3. reboot

I tried it 10 times and only once the problem didn't occur. 

Actual Results:  




With Google I found the same problem upstream on the linux-kernel mailinglist e.g.
http://marc.free.net.ph/message/20050113.145029.a63abe83.en.html
I will try the proposed patch and report ...

[Comment 1 Horst Prote 2005-01-21 06:31:17 UTC]

Created attachment 49106 [details, diff]
Patch of neighbor.c for hardened-sources-2.4.28-r2

[Comment 2 Horst Prote 2005-01-21 06:31:55 UTC]

Tried the proposed patch from
http://marc.free.net.ph/message/20050113.145029.a63abe83.en.html
and couldn't reproduce the problem in three reboots on a machine with
hardened-sources-2.4.28-r2 (my diff see Attachement).
Will test a gentoo-sources-2.4.28-r5 machine too (it's a rather slow one,
so kernel compilation will take some time).

[Comment 3 Horst Prote 2005-01-21 07:55:33 UTC]

Created attachment 49110 [details, diff]
Patch for neighbor.c of gentoo-sources-2.4.28-r5

Tree reboots: No problem seen.

[Comment 4 Horst Prote 2005-01-21 07:59:10 UTC]

Comment on attachment 49110 [details, diff]
Patch for neighbor.c of gentoo-sources-2.4.28-r5

Three reboots: No problem seen.

[Comment 5 Adam Mondl (RETIRED) 2005-01-21 19:16:13 UTC]

I have experienced this same problem on hardened-sources.  As far as I can tell the patch fixes the problem for me as well.  I have added it to the patchset for hardened-sources-2.4.28-r4.

[Comment 6 Tim Yamin (RETIRED) 2005-02-17 10:14:16 UTC]

Fixed in 2.4.28-r6; thanks!