Hi all, I'm running an updated HEAD kernel and got a page fault in ifindex_alloc_locked() in if.c. I figured that the problem was caused by the (pluggable) network card of my laptop and found that during the initialization of the interface, cb_event_thread() takes the giant lock and up the call chain in if_alloc(), we call IFNET_WLOCK() and assert on the RW locks in ifindex_alloc_locked(). It is in the asset macro IFNET_WLOCK_ASSERT() I see the page fault.
I looked up some recent related changes and noticed the following comment in one of the check-ins in- http://svn.freebsd.org/viewvc/base/head/sys/net/if.c "Break out allocation of new ifindex values from if_alloc() and if_vmove(), and centralize in a single function ifindex_alloc(). Assert the IFNET_WLOCK, and add missing IFNET_WLOCK in if_alloc(). This does not close all known races in this code." So I think I have hit one of those fault conditions. Apparently the giant lock code was removed and added back recently - http://svn.freebsd.org/viewvc/base/head/sys/dev/pccbb/pccbb.c I believe that the root cause is that ifnet_rw is a non sleepable exclusive RW lock and we have taken the exclusive sleep mutex Giant before that. Any pointers and suggestions are welcome. Many thanks, Harsha _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
