From owner-freebsd-bugs Wed Jan 15 05:30:04 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.4/8.8.4) id FAA29424 for bugs-outgoing; Wed, 15 Jan 1997 05:30:04 -0800 (PST) Received: (from gnats@localhost) by freefall.freebsd.org (8.8.4/8.8.4) id FAA29407; Wed, 15 Jan 1997 05:30:02 -0800 (PST) Date: Wed, 15 Jan 1997 05:30:02 -0800 (PST) Message-Id: <199701151330.FAA29407@freefall.freebsd.org> To: freebsd-bugs Cc: From: Prisoner Subject: Re: kern/2494: page faults Reply-To: Prisoner Sender: owner-bugs@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk The following reply was made to PR kern/2494; it has been noted by GNATS. From: Prisoner To: Joerg Wunsch 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/