Date: Sat, 24 Feb 2001 15:55:42 -0800 (PST) From: John Baldwin <jhb@FreeBSD.org> To: Warner Losh <imp@harmony.village.org> Cc: current@FreeBSD.org, Bruce Evans <bde@zeta.org.au> Subject: Re: Today's panic :-) Message-ID: <XFMail.010224102557.jhb@FreeBSD.org> In-Reply-To: <200102240658.f1O6wiW85748@harmony.village.org>
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On 24-Feb-01 Warner Losh wrote: > In message <Pine.BSF.4.21.0102241719140.26925-100000@besplex.bde.org> Bruce > Evans writes: >: It seems to be another trap while holding sched_lock. This should be >: fatal, but the problem is only detected because trap() enables >: interrupts. Then an interrupt causes bad things to happen. Unfortunately, >: the above omits the critical information: the instruction at sw1b+0x6b. >: There is no instruction at that address here. It is apparently just an >: access to a swapped-out page for the new process. I can't see how this >: ever worked. The page must be faulted in, but this can't be done while >: sched_lock is held (not to mention after we have committed to switching >: contexts). > > sw1b+0x6b is ltr %si > > I note that this doesn't happen when the disks are clean on boot, but > does happen when they are dirty. The kernel is as of a cvsup 3pm MST > today. The kernel from 1am last night doesn't seem to have this > problem. Other people have reported this and I can't reproduce this. The one case I managed to track down so far involved proc0 having pcb_ext bogusly set, resulting in cpu_switch() setting up a bogus GDT entry for a TSS and thus generating a GPF which is the trap you see. The enable_intr() in trap() then sends things downhill fast. I'm not sure yet why processes are having pcb_ext bogusly set. Hmm. Make sure you have rev 1.35 or later of pcb.h. Also, try build a kernel from scratch from fresh sources.. > Warner -- John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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