Occasional errors "rt_build: if_initrt: Cannot allocate memory" on idle machines with enough memory

[liweitianux]

Hi all,

I have two DragonFly machines running dhcpcd, and they occasionally emit errors rt_build: if_initrt: Cannot allocate memory. However, I don't believe the machines were actually lacking memory. One machine is bare metal with 8G RAM and 16G swap, and the swap was almost unused (only 16M in use). The other machine is a VirtualBox VM with 2G RAM and 2G swap; it was just idle and used no swap.

On the bare metal machine:

% grep if_initrt /var/log/messages
Dec 14 11:40:27 microserver dhcpcd[428]: rt_build: if_initrt: Cannot allocate memory
Dec 14 19:33:28 microserver dhcpcd[428]: rt_build: if_initrt: Cannot allocate memory
Feb  8 17:36:54 microserver dhcpcd[428]: rt_build: if_initrt: Cannot allocate memory
Feb 11 18:07:30 microserver dhcpcd[428]: rt_build: if_initrt: Cannot allocate memory

On the VM:

% grep if_initrt /var/log/messages
Feb 15 23:33:26 dfly dhcpcd[426]: rt_build: if_initrt: Cannot allocate memory

I'll keep monitoring this and hope to get more details.

[rsmarples]

We need to check if-bsd.c in the if_initrt function and see how much memory the kernel wants us to allocate to receive the route messages.

[rsmarples]

I have seen this once when working the kernel rtsock netmask patch.

[liweitianux]

Nice catch. Awesome 👍