Date: Fri, 1 Apr 2005 01:03:14 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: John Baldwin <jhb@FreeBSD.org> Cc: William Michael Grim <wgrim@siue.edu> Subject: Re: 4BSD Scheduler Problem on 5.3 Message-ID: <Pine.NEB.3.96L.1050401010153.51321B-100000@fledge.watson.org> In-Reply-To: <200503311716.52034.jhb@FreeBSD.org>
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On Thu, 31 Mar 2005, John Baldwin wrote: > On Thursday 31 March 2005 03:38 pm, William Michael Grim wrote: > > Hello. > > > > I keep having kernel panics every couple weeks on my system. It occurs in > > the sched_switch() function. There are several other statements in the > > backtrace involving "??"; what are those? > > > > I have attached the dump output and system info to this email. Any > > feedback would be helpful. > > > > Thanks so much for your help. > > The real trace ends with Xint0x80_syscall(). The rest after that is > garbage memory. Your real problem is in exit1() or ttywakeup(). Since > ttywakeup() doesn't call exit1() (AFAIK), the exit1() frame is probably > bogus (gdb doesn't grok trapframes maybe?) and the real bug is a NULL > pointer deref in ttywakeup(). Perhaps it's a bug in the ptc driver? > (ptcopen is in the trace). What is the ptc driver anyway? I think we have a race in -STABLE relating to tty wakeups and open/close/device teardown. I've seen a panic relating to sio during a tty close on RELENG_5 about 5-6 months ago, but was unable to get a dump. Scott has since fixed dumps with twe, but I've not yet been able to get the bug to recur. I'll give it another try. Robert N M Watson
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