Date: Mon, 24 Sep 2001 21:45:43 +0200 From: Wilko Bulte <wkb@freebie.xs4all.nl> To: John Baldwin <jhb@FreeBSD.org> Cc: Garrett Wollman <wollman@khavrinen.lcs.mit.edu>, current@FreeBSD.org Subject: Re: Seen this lock order reversal? Message-ID: <20010924214543.A16350@freebie.xs4all.nl> In-Reply-To: <XFMail.010924123332.jhb@FreeBSD.org>; from jhb@FreeBSD.org on Mon, Sep 24, 2001 at 12:33:32PM -0700 References: <20010923204929.A11867@freebie.xs4all.nl> <XFMail.010924123332.jhb@FreeBSD.org>
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On Mon, Sep 24, 2001 at 12:33:32PM -0700, John Baldwin wrote: > > On 23-Sep-01 Wilko Bulte wrote: > > On Thu, Sep 20, 2001 at 07:40:52PM +0200, Wilko Bulte wrote: > >> On Wed, Sep 19, 2001 at 01:32:28PM -0700, John Baldwin wrote: > >> > > >> > On 19-Sep-01 Wilko Bulte wrote: > >> > > On Tue, Sep 18, 2001 at 03:01:25PM -0700, John Baldwin wrote: > >> > >> ... > >> > >> > >> p_flag to p_sflag which changed its locking semantics.) > >> > > > >> > > Another one, on a -current from yesterday, on -alpha: > >> > > > >> > > lock order reversal > >> > > 1st 0xfffffc00007fcef0 clk @ ../../../alpha/alpha/clock.c:702 > >> > > 2nd 0xfffffc00007f65d8 callout @ ../../../kern/kern_timeout.c:225 > >> > > ds10# > >> > > >> > Hmm, ok, that one is new and is a problem. Can you turn on WITNESS_DDB > >> > (it's > >> > available as the debug.witness_ddb sysctl and loader variableas well) and > >> > then > >> > get me a traceback in ddb? > >> > >> I built a GENERIC with WITNESS_DDB. Sofar (of course... :-/ ) no > >> reproduction of the problem. I'm running buildworlds, any other good > >> suggestions to help trigger it are welcome > > > > Bah. I cannot reproduce this on my DS10. > > > > Is there any reason to assume that specifying CPUTYPE ev56 has any > > influence on the lock order reversal? By default world is built with > > ev4, but I have gone to ev56 now. Rumor has it that results in 'less > > buggy' code. > > No. Hmmm. You didn't have any KTR traces enabled did you? > > Hmm, that first one is in sysbeep() (the clk one) Ah! <grr>It is easy to nuke the system once you know what is wrong: type ^G on the console and *bang* you are in DDB ;) -- | / o / /_ _ email: wilko@FreeBSD.org |/|/ / / /( (_) Bulte Arnhem, The Netherlands To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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