Date: Fri, 27 Jul 2012 15:42:49 +0100 From: Attilio Rao <attilio@freebsd.org> To: Andrew Boyer <aboyer@averesystems.com> Cc: FreeBSD Stable Mailing List <freebsd-stable@freebsd.org>, John Baldwin <jhb@freebsd.org>, Andriy Gapon <avg@freebsd.org> Subject: Re: IPMI hardware watchdogs Re: dell r420/r320 stable/9 Message-ID: <CAJ-FndCsSZmKTif7Mn%2BZSMX1rbkgkjytRRY5viGimATDMm5RXQ@mail.gmail.com> In-Reply-To: <23294764-F30B-4732-8C41-3F0ECA5F273C@averesystems.com> References: <1343350238.12294.10.camel@powernoodle.corp.yahoo.com> <23294764-F30B-4732-8C41-3F0ECA5F273C@averesystems.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Fri, Jul 27, 2012 at 3:33 PM, Andrew Boyer <aboyer@averesystems.com> wro= te: > > 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=3Drevision&revision=3D237839 >> http://svnweb.freebsd.org/base?view=3Drevision&revision=3D221121 >> > > > On a somewhat related note: We noticed recently that you can't pet or dis= able the IPMI hardware watchdog once SCHEDULER_STOPPED() is true. This mea= ns it can fire unexpectedly while you're dumping core or rebooting, dependi= ng on how long the timeout was on the pet before the panic. The ipmi drive= r will need to process the command differently if the scheduler is stopped.= I haven't had time to look at a fix yet. I recall I fixed that internally for SV, but the key here is that we need to find an unified (or a default policy). More specifically, do we want the watchdog also covers the kernel dump part (because of possible deadlocks when dumping). If the answer is yes, we likely need pat the watchdog from within the dumping cycle itself. If the answer is no, then we can just disable it when entering the panic path. But anyway, we need to identify a default policy that makes sense first. Attilio --=20 Peace can only be achieved by understanding - A. Einstein
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAJ-FndCsSZmKTif7Mn%2BZSMX1rbkgkjytRRY5viGimATDMm5RXQ>