Re: [PATCH 11/11] svcgssd: Wait for nullrpc channel if not available

Doug Nazar
2020-07-18T18:07:43Z

On 2020-07-18 11:55, J. Bruce Fields wrote:

> So, is there a race here that could result in a hang, and has anyone
> seen it in practice?
>
> Just curious. Thanks for doing this.--b.

Not a hang, with the existing code, svcgssd will just exit. I'd have to
go and restart it after boot. I'm assuming a systemd setup would just
restart it automatically.
On my original systems I'd configured it to force load the modules, but
I'd forgotten about that (it was about 10 years ago) when I built this
new box last month.

As mentioned in the other email, sunrpc is loaded from an initramfs that
doesn't have any of the gss modules. When nfsd is started (after
svcgssd) it'll then load the gss modules but by then it's too late.

It seems to be a standard Gentoo setup. I just checked the default
kernel config for genkernel (their kernel & initramfs builder) and it
has all the rpc & nfs as modules, with the initramfs not supporting
Kerberos.

Looks like Debian modprobes rpcsec_gss_krb5 before starting rpc.svcgssd.

So with this waiting for the file to appear, and I'm planning on adding
a conditional module load to the Gentoo rpc.svcgssd init script, things
should be as bulletproof as I can make it.

Doug