Re: BUG in __key_instantiate_and_link(): unable to handle kernelpaging request at 0000632e6472616f

From: Andre Tomt
Date: Mon Jun 18 2012 - 05:04:58 EST


On 16. juni 2012 21:59, Myklebust, Trond wrote:
It looks to me as if the legacy upcall code is assuming that there can
be no more than 1 upcall at a time: there is only a single
idmap->idmap_key_cons, which gets assigned in nfs_idmap_legacy_upcall
and then read in idmap_pipe_downcall.

Bryan, can you look into this? I suspect that we need a mutex or
something like that (for the legacy upcall case only) to ensure that
nobody overwrites the idmap->idmap_key_cons while an upcall is in
progress.

Andre, if you want idmapper scalability, then you should rather use the
new idmapper upcall. You need a recent version of the nfs-utils package,
the keyutils package, and they you should add an 'id_resolver' line
to /etc/request-keys.conf as per the nfsidmap manpage.

Indeed, using keyutils did avoid the crashes here, 40 hours and counting.

Are there any downsides of having keyutils w/ id_resolver on by default in a distribution? Would it break older kernels or nfs-utils (just not getting used is fine, obviously)?
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