Date: Sat, 06 Oct 2001 22:19:23 -0700 From: Doug Barton <DougB@DougBarton.net> To: Bruce Evans <bde@zeta.org.au> Cc: freebsd-current@FreeBSD.ORG Subject: Re: panic: blockable sleep lock (sx) allproc @ /usr/local/src/sys/kern/kern_proc.c:212 Message-ID: <3BBFE5DB.2831C139@DougBarton.net> References: <20011007142123.A6012-100000@delplex.bde.org>
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Bruce Evans wrote:
>
> On Sat, 6 Oct 2001, Doug Barton wrote:
>
> > Bruce Evans wrote:
> >
> > > This is a well-know bug in printf(9). The TIOCCONS ioctl always gave
> > > non-deterministic crashes. Now it gives determinstic panics when
> > > pintf() is called while sched_lock is held. Work-around: don't use
> > > anything that uses TIOCCONS (xconsole?).
> >
> > Yes, I'm using xconsole, and I find it very useful. How hard would it be
> > to actually fix this? I'm still crashing fairly often with this same exact
> > problem.
>
> Thanks. No one actually acknowledged my diagnosis of this bug before (I
> don't use xconsole and haven't got around to trying it).
>
> Is using xconsole significantly better than "tail -f /var/log/messages"?
Yes... for a couple reasons. It's less processes, it has a clever little
thing where it changes the icon title if something has written a message to
it, I can do clever things like 'ln -s /dev/console
$HOME/.xsession-errors', etc. Admittedly, there isn't anything here that I
couldn't reproduce, or live without. But xconsole is enabled standard with
xdm, so it's something that should work.
> Both have the problem of not being able to show any output if userland
> can't run, but I think this problem would be only slightly larger for
> syslogd and tail combined than for xconsole. A fix would involve more
> buffering in the kernel, or perhaps more elegantly, dropping TIOCCONS
> and putting "tail -f"-like support in dmesg.
Well, there is the console facility for syslog now, so some of this is
done already. But as I said, in the end xconsole should work. BTW, I can
confirm that without xconsole running, I haven't crashed yet today, that's
about 12 hours worth... previously the longest I lasted was about 4 hours.
Doug
--
"We will not tire, we will not falter, and we will not fail."
- George W. Bush, President of the United States
September 20, 2001
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