freebsd stable - Feb 2012 - lock violation in unionfs (9.0-STABLE r230270)

http://www.freebsd.org/cgi/query-pr.cgi?pr=165087

Occurs simply trying to use unionfs:
mount -t unionfs -o noatime /usr /mnt

insmntque: mp-safe fs and non-locked vp: 0xfffffe01d96704f0 is not  
exclusive locked but should be
KDB: enter: lock violation

Its possible to continue tho.
Then locks encounter on every file/dir access under mounted path.
It can be resumed from KDB, but sometimes leads to deadlock and system  
freezes at "db> " prompt.

2012/2/13, Pavel Polyakov <bsd@kobyla.org>:
> http://www.freebsd.org/cgi/query-pr.cgi?pr=165087
>
> Occurs simply trying to use unionfs:
> mount -t unionfs -o noatime /usr /mnt
>
> insmntque: mp-safe fs and non-locked vp: 0xfffffe01d96704f0 is not
> exclusive locked but should be
> KDB: enter: lock violation
Pavel,
can you give a spin to this patch?:
http://www.freebsd.org/~attilio/unionfs_missing_insmntque_lock.patch

I think that the unlocking is due at that point as the vnode lock can
be switch later on.

Let me know what you think about it and what the test does.
Attilio


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