Bug#685625: libgeom: segfaults on large kern.geom.confxml

[Steven Chamberlain]

retitle 685625 libgeom: segfaults on large kern.geom.confxml
reassign 685625 src:freebsd-utils
affects 685625 grub-common
found 685625 9.0+ds1-7
user debian-bsd at lists.debian.org
usertags 685625 kfreebsd
thanks

Hi!

I'm reassigning this because GRUB can't really avoid this crash in libgeom.

I don't see anything else odd about the XML except for its size.  It
seems, then that 6510 snapshots makes the kern.geom.confxml larger than
libgeom can handle?  Though I didn't find any hard-coded buffer sizes.

Since ZFS is supposed to be the filesystem without limits etc. I still
think it's important to fix this.

Thank you very much for your help.

I suppose you could try now removing those accidental snapshots of swap
and see if it starts to work again.  If so, it might be interesting to
know the approximate size of the kern.geom.confxml output at which
grub-probe starts to work again.

BTW:  the script bundled in /etc/cron.daily/zfsutils has a nice
algorithm for creating + keeping up to 'n' snapshots, and deletes old
ones in a way that prefers to keep mostly the more recent ones, with an
exponential decay.  It's very neat.

Regards,
-- 
Steven Chamberlain
steven at pyro.eu.org