Kernel lockmgr races LK_UPGRADE against LK_SHARED...

[Stephan Uphoff]

On Wed, 2005-06-15 at 20:41, Mohan Srinivasan wrote:
> This is on 4.x, but I'm posting to current, it's likely also
> an issue on current. Posting here hoping someone can shed 
> more info on this lockmgr race.
> 
> I've into a bug where process 1 successfully LK_UPGRADEs a
> vnode lock (from shared to excl) and process 2 successfully 
> acquires the shared lock on that same vnode. I am not sure
> what order the locks were acquired, it's not possible to 
> infer that from the core.
> 
> Does this bug ring a bell with anyone ? If it does, can they 
> shed any light/info they might have on this ?
> 
> thanks
> 
> mohan

Reminds me of:
http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/69934

Stephan