From owner-freebsd-current Sun Apr 28 12:14:17 2002 Delivered-To: freebsd-current@freebsd.org Received: from fledge.watson.org (fledge.watson.org [204.156.12.50]) by hub.freebsd.org (Postfix) with ESMTP id A24A637B41C for ; Sun, 28 Apr 2002 12:14:09 -0700 (PDT) Received: from fledge.watson.org (fledge.pr.watson.org [192.0.2.3]) by fledge.watson.org (8.11.6/8.11.6) with SMTP id g3SJDqw99048; Sun, 28 Apr 2002 15:13:52 -0400 (EDT) (envelope-from robert@fledge.watson.org) Date: Sun, 28 Apr 2002 15:13:52 -0400 (EDT) From: Robert Watson X-Sender: robert@fledge.watson.org To: Matthew Dillon Cc: current@FreeBSD.ORG Subject: Re: Page fault in swp_pager_meta_build() In-Reply-To: <200204281711.g3SHBbY53495@apollo.backplane.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Sun, 28 Apr 2002, Matthew Dillon wrote: > > :(Matt gets CC'd because he's just unlucky :-) > : > :This system is (as always) a pxeboot'd nfsroot'd dual processor box. This > :time, however, it's running straight GENERIC from the main tree instead of > :the MAC branch. The box network boots, does a buildkernel -j 8, and then > :reboots. It currently has no configured swap, suggesting that things > :broke down when it tried to think about using some swap. Not sure how > :many loops it took to get to this, but I've seen a couple of different > :panics that I'll be posting about as they recur. I'm actually trying to > :track an odd mbuf/nfs interaction... > > No idea, but the last time someone had a weird swap issue it > turned out that they had swapon'd the same swap partition twice. > The system's checks are not sufficient if you swapon the same device > from different mounts. So check that first. It currently has no swap started at all, which is one reason I was rather puzzled to see this panic: 192.168.50.1:/cboss/devel/nfsroot/crash2.cboss.tislabs.com / nfs ro 0 0 proc /proc procfs rw 0 0 /dev/ad0s1e /mnt ufs rw 0 0 > The swap code preallocates its bitmap space, the hash table array is > malloc'd once at boot time, and the swblock is zalloc()'d. From the > looks of it the hash chain either got corrupted somehow or part of > the kernel's KVM space containing either the hash table or > the swblock's got corrupted. Unless someone worked on the swap > code recently I would focus on either the memory subsystem or > on unrelated kernel subsystems blowing up KVK. Should it even be hitting this code if swap hasn't been enabled? I've run into a couple of other weird bugs and wouldn't be surprised if there is a memory allocation problem. The problem I was actually trying to reproduce with these two crash boxes was one where the socket used by NFS get zero'd, resulting in a null pointer dereference. The other one is in odd panic in the mutex code during an early VFS operation. Robert N M Watson FreeBSD Core Team, TrustedBSD Project robert@fledge.watson.org NAI Labs, Safeport Network Services To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message