on 27/07/2012 17:33 Andrew Boyer said the following: > > On Jul 26, 2012, at 8:50 PM, Sean Bruno wrote: > >> For the time being I had to revert the following from my stable/9 tree. >> Otherwise I would get a kernel panic on shutdown from ipmi(4). >> >> http://svnweb.freebsd.org/base?view=revision&revision=237839 >> http://svnweb.freebsd.org/base?view=revision&revision=221121 >> > > > On a somewhat related note: We noticed recently that you can't pet or disable > the IPMI hardware watchdog once SCHEDULER_STOPPED() is true. This means it > can fire unexpectedly while you're dumping core or rebooting, depending on > how long the timeout was on the pet before the panic. The ipmi driver will > need to process the command differently if the scheduler is stopped. I > haven't had time to look at a fix yet.
Yeah, I noticed that unlike most (all?) other watchdog drivers where watchdog re-arming is a very basic operation like doing one I/O the IPMI watchdog does some more complex stuff which involves waiting on another thread. I think that this may be a little bit too much for a reliable watchdog driver. At least, as you note, this definitely won't work for the panic case where only one thread is left running. I guess that the driver should check for that case and do a direct operation instead of enqueueing a request and waiting for another thread to execute it. -- Andriy Gapon _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
