From owner-freebsd-stable Mon Feb 5 9:34:59 2001 Delivered-To: freebsd-stable@freebsd.org Received: from fw.wintelcom.net (ns1.wintelcom.net [209.1.153.20]) by hub.freebsd.org (Postfix) with ESMTP id 90F8D37B401 for ; Mon, 5 Feb 2001 09:34:38 -0800 (PST) Received: (from bright@localhost) by fw.wintelcom.net (8.10.0/8.10.0) id f15HYZe03346; Mon, 5 Feb 2001 09:34:35 -0800 (PST) Date: Mon, 5 Feb 2001 09:34:35 -0800 From: Alfred Perlstein To: Thomas Stratmann Cc: freebsd-stable@FreeBSD.ORG Subject: Re: ktrace sync'ing before panic Message-ID: <20010205093435.N26076@fw.wintelcom.net> References: <3A7EA2FA.E08B958D@ruhr-uni-bochum.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <3A7EA2FA.E08B958D@ruhr-uni-bochum.de>; from thomas.stratmann@ruhr-uni-bochum.de on Mon, Feb 05, 2001 at 01:56:27PM +0100 Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG * Thomas Stratmann [010205 05:04] wrote: > Hi everyone, > > I had a problem once on a 4.1-stable which does not seem to be fixed by > now. I had mount cause panic under certain circumstances and went to > find the error, first doing ktrace on the call. The result was an empty > ktrace.out as the output was not synchronized/written out do disk before > the actual kernel panic. I went into kern_ktrace.c and inserted a > VOP_FSync call inside ktrwrite and it worked: after the panic, one could > see the last kernel action was a call to mount (into the kernel) - the > first stage of success in debugging. > > I believe the issue of syncing is a tradeoff between speed and > reliability in the (rare) case of a panic. > > One should consider introducing an option to the ktrace call for this - > if the manpage will be elaborate enough about the issue, even > non-hackers will be able to give more precise error mailings. This is an excellent idea, can you open a PR about it? -- -Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org] "I have the heart of a child; I keep it in a jar on my desk." To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message