# udev unreliable_kernel_warning

## thomasn

Hi,

Just updating a system as usual with 

```
emerge -auDN world
```

 gave me the following warning when udev was updated:

```

WARN: setup

If you want to use udev reliable you should update

to at least kernel version 2.6.22!

LOG: preinst

Moving //etc/modprobe.d//pnp-aliases to pnp-aliases.conf

Moving //etc/modprobe.d//blacklist to blacklist.conf

LOG: postinst

restarting udevd now.

persistent-net does assigning fixed names to network devices.

If you have problems with the persistent-net rules,

just delete the rules file

        rm /etc/udev/rules.d/70-persistent-net.rules

and then reboot.

This may however number your devices in a different way than they are now.

WARN: postinst

If you build an initramfs including udev, then please

make sure that the /sbin/udevadm binary gets included,

and your scripts changed to use it,as it replaces the

old helper apps udevinfo, udevtrigger, ...

mount options for directory /dev are no longer

set in /etc/udev/udev.conf, but in /etc/fstab

as for other directories.

LOG: postinst

For more information on udev on Gentoo, writing udev rules, and

         fixing known issues visit:

         http://www.gentoo.org/doc/en/udev-guide.xml

```

I've read the udev guide but don't see in there how to judge what "unreliable" might mean. FWIW this is an AWS EC2 instance, upgrading from the 2.6.18 kernel I'm currently using would be a PITA -- so should I ignore this warning? Or downgrade to an earlier version of udev and mask upgrades?

If anyone can point me to docs that would tell me why 2.6.22 is required for udev-141 and what is likely to break on 2.6.18 I'd be really grateful.

Thomas.

----------

