On 16 July 2013 12:32, Andriy Gapon <a...@freebsd.org> wrote: > vmcore.0 was useless for some reason - an interesting address was not > accessible.
Eek. > vmcore.1 seems to be very similar and is actually useful. Oh good. > This problem looks like an interesting deadlock involving ZFS and VFS and > vnode > shortage. > The most obvious things are that many threads could not allocate a new vnode > and > are waiting in getnewvnode_reserve and also many threads are stuck waiting on > vnode locks held by the former threads. > In effect, they all wait for vnlru, which in turn is stuck in > zfs_freebsd_reclaim on z_teardown_lock. > That lock is held by a thread doing a rollback ioctl. > And that thread waits for zfs sync thread to actually perform the rollback. > The sync thread waits on zfs quiesce thread to declare the current transaction > group as quiesced. > The quiesce thread, obviously, waits for all operations running in the current > transaction group to complete. > Some of those operations are e.g. VOP_CREATE -> zfs_create. They already > started a zfs transaction (as a part of the current transaction group) and > they > execute zfs_mknode which needs a new vnode. So these threads are waiting for > a > new vnode and do not let the current transaction group become quiesced. > GOTO beginning. > > Compressing the above description to the extreme, it boils down to: ZFS needs > a > new vnode from vnlru and is waiting on it, while vnlru has to wait on ZFS. :( So it's a deadlock. Ok, so what's next? -adrian _______________________________________________ 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"
