On Sat, Nov 24, 2012 at 3:08 AM, Ryan Stone <ryst...@gmail.com> wrote: > Today I saw a spurious witness warning for "acquiring duplicate lock of > same type". The root cause is that when running mtx_destroy on a spinlock > that is held by the current thread, mtx_destroy calls spinlock_exit() > before calling WITNESS_UNLOCK, which opens up a window in which the CPU can > be interrupted and attempt to acquire another spinlock of the same type as > the one being destroyed. This patch should fix it:
I seriously wonder why right now we don't assume the lock is unheld. There are likely historically reasons for that, but I would like to know which one are those and eventually fix them out. FWIK, all the other locking primitives assume the lock is already unheld when destroying and I think it would be good to have that for mutexes as well. Can you please show which lock triggers the panic you saw? Thanks, Attilio -- Peace can only be achieved by understanding - A. Einstein _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
