[karmic] udev requires new kernel, breaks on EC2

[Andreas Hasenack]

Binary package hint: udev

At some point, udev started using signalfd(2), which requires a new kernel. IIRC it was implemented in 2.6.25.

While this is not a problem for karmic itself, it is a problem for EC2, which runs an older kernel. If one tries to upgrade the current jaunty image to karmic, udev won't start anymore:

root@ip-10-244-15-193:~# udevd
error getting signalfd

strace shows:
8706 SYS_327(0xffffffff, 0xbfc5238c, 0x8, 0, 0x2f4ff4) = -1 ENOSYS (Function not implemented)
8706 write(2, "error getting signalfd\n", 23) = 23

The same happens when booting Alestic's karmic image (ami-19a34270). Out of the box it still works, because it has udev 142, but dist-upgrade it and udev breaks too.

[Eric Hammond (esh)]

Running the latest udev (144) on a Karmic EC2 instance causes the network to not come back up after a reboot because of this problem (Andreas found this out, but I confirmed and thought it was also worth mentioning this severe effect in this bug). I'm not sure this is really a udev bug; the right answer might be to build a newer kernel for EC2, though I can't judge the effort required to "fix" either side.

[Scott James Remnant (Canonical) (canonical-scott)]

Upstart will also soon start requiring signalfd()

The EC2 kernel should be updated

[Eric Hammond (esh)]

By "won't fix" I assume this means that it will not be possible to upgrade an instance running an Intrepid/Jaunty AMI to Karmic and expect it to keep running on the older Intrepid/Jaunty kernel. This makes sense given the issues with the kernel and the inability to upgrade a kernel on a running instance in the EC2 environment.

I assume that "won't fix" does not mean that the plan is to not build a Karmic kernel.

[Scott Moser (smoser)]

You are correct that there will not be a change to karmic's udev to
support running on top of a kernel without signalfd support. Thus, karmic
images will not run with older kernel images.

> I assume that "won't fix" does not mean that the plan is to not build a
> Karmic kernel.

Also correct. We're working on getting both Jaunty and Karmic kernel
images.

[Scott Moser (smoser)]

I'm re-opening this bug. We'll leave it open until there is a solution provided.

The solution is likely to be karmic kernels on amazon.

[Eric Hammond (esh)]

The fix for this will be LP#418130 (building a Karmic kernel), so I think it's appropriate to call this a duplicate.

[C.J. Collier (cjcollier)]

This bug is not EC2-specific. This effects all Xen HVM virtual machines.

[C.J. Collier (cjcollier)]

Let me clarify: all Xen HVM virtual machines which depend on the paravirt network driver (only available in the 2.6.18 kernel, AFAICT)