Date: Tue, 16 Jul 2002 11:10:05 -0700 From: Alfred Perlstein <bright@mu.org> To: Andrew Gallatin <gallatin@cs.duke.edu> Cc: Andrew Kolchoogin <andrew@snark.rinet.ru>, current@freebsd.org Subject: Re: VOP_GETATTR panic on Alpha Message-ID: <20020716181005.GW77219@elvis.mu.org> In-Reply-To: <15668.23528.719956.574605@grasshopper.cs.duke.edu> References: <xzpele33kq0.fsf@flood.ping.uio.no> <20020716145107.GA69162@snark.rinet.ru> <15668.23528.719956.574605@grasshopper.cs.duke.edu>
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* Andrew Gallatin <gallatin@cs.duke.edu> [020716 10:46] wrote:
>
> Andrew Kolchoogin writes:
> > Hi!
> >
> > On Tue, Jul 16, 2002 at 02:45:11PM +0200, Dag-Erling Smorgrav wrote:
> >
> > > The following panic is 100% reproducable - it happens whenever I boot
> > > a recent kernel on Alpha, just before init(8) starts getty(8) on the
> > > console:
> > sorry, kernel from today's sources at 17:38 works just fine.
> >
> > Yet another question about kernel core dumps: what should I do to get one?-)
> > Why "panic" from debugger on i386 gives core dump and reboots the system
> > and "panic" from debugger on Alpha does not?
> >
>
> Because, as BDE says, that crashdumps work at all is mosty accidental.
>
> On alpha, a random kernel thread is waking up, and is unable to go
> back to sleep because of the panicstr hack msleep:
>
> mtx_lock_spin(&sched_lock);
> if (cold || panicstr) {
> /*
> * After a panic, or during autoconfiguration,
> * just give interrupts a chance, then just return;
> * don't run any other procs or panic below,
> * in case this is the idle process and already asleep.
> */
> if (mtx != NULL && priority & PDROP)
> mtx_unlock(mtx);
> mtx_unlock_spin(&sched_lock);
> return (0);
> }
>
>
> We need to somehow let only interrupt threads and the panic'ed process
> run after a panic. I have no idea how to do this in a clean,
> low-impact way.
>
> Drew
>
> PS: I was trying to make crashdumps fail on x86 by increasing HZ. But
> I cannot. I have no idea why this only happens on alpha.
um, psuedocode...
for ithreads, td->td_flags |= TD_ITHREAD
for panicing thread, td->td_flags |= TD_INPANIC
if ((cold || panicstr) && (td->td_flags & (TD_ITHREAD|TD_INPANIC)) != 0) {
?
--
-Alfred Perlstein [alfred@freebsd.org]
'Instead of asking why a piece of software is using "1970s technology,"
start asking why software is ignoring 30 years of accumulated wisdom.'
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