Date: Wed, 15 Jan 1997 05:30:02 -0800 (PST) From: Prisoner <spatula@gulf.net> To: freebsd-bugs Subject: Re: kern/2494: page faults Message-ID: <199701151330.FAA29407@freefall.freebsd.org>
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The following reply was made to PR kern/2494; it has been noted by GNATS.
From: Prisoner <spatula@gulf.net>
To: Joerg Wunsch <joerg_wunsch@uriah.heep.sax.de>
Cc: FreeBSD-gnats-submit@freebsd.org
Subject: Re: kern/2494: page faults
Date: Wed, 15 Jan 1997 07:18:52 -0600 (CST)
On Wed, 15 Jan 1997, J Wunsch wrote:
> No, it didn't test out fine, apparently. A FreeBSD `make world' is
> commonly agreed to be a much better hardware test than anything you
> else.
Perhaps I should rephrase: everything I can do to test it has failed to
show a problem, including 9-10 hours each of several diagnostic programs
running in a much lamer operating system.
> Unless your page faults repeatedly appear at similar addresses, all
> this smells like bad RAM. You need at least to provide us with kernel
> stack traces if the fault is repeatable at a single spot.
The page fault is almost always exactly the same. Here's the debugger
information from the last (and most common) fault:
fault virtual address = 0x7200c4c
fault code = supervisor read, page not present
instruction pointer = 0x8:0xf017c4b4
code segment = base 0x0, limit 0xfffff, type 0x1b
= DPL 0, pres 1, def32 1, gran 1
processor eflags = trace/trap, interrupt enabled, resume, IOPL=0
current process = 4 (update)
interrupt mask =
kernel: type 12 trap, code=0
breakpoint at _ffs_update +0xa4: cmpl $0x1,0x52c(%ebx)
It's always within a few instructions to this location. I am now
experimenting with eliminating various programs from running to see if
anything is hosing things up. I think I have a conclusive result, but I
don't want to say anything until I can prove it.
Nick
--
"Your views are not important"
- Nyder, from Doctor Who: Genesis of the Daleks
Nick Johnson, not to be trifled with. http://www.gulf.net/~spatula/
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