From owner-freebsd-current@FreeBSD.ORG Thu Apr 22 14:19:49 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5FCBF16A4CE; Thu, 22 Apr 2004 14:19:49 -0700 (PDT) Received: from fledge.watson.org (fledge.watson.org [204.156.12.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id 046CC43D2F; Thu, 22 Apr 2004 14:19:49 -0700 (PDT) (envelope-from robert@fledge.watson.org) Received: from fledge.watson.org (localhost [127.0.0.1]) by fledge.watson.org (8.12.11/8.12.11) with ESMTP id i3MLJWeN027127; Thu, 22 Apr 2004 17:19:32 -0400 (EDT) (envelope-from robert@fledge.watson.org) Received: from localhost (robert@localhost)i3MLJW9P027124; Thu, 22 Apr 2004 17:19:32 -0400 (EDT) (envelope-from robert@fledge.watson.org) Date: Thu, 22 Apr 2004 17:19:32 -0400 (EDT) From: Robert Watson X-Sender: robert@fledge.watson.org To: "Simon L. Nielsen" In-Reply-To: <20040422211730.GA801@zaphod.nitro.dk> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII cc: freebsd-current@FreeBSD.org Subject: Re: panic: mutex Giant not owned at src/sys/security/mac/mac_net.c:355 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 22 Apr 2004 21:19:49 -0000 On Thu, 22 Apr 2004, Simon L. Nielsen wrote: > I have a reproduceable panic when I have MAC enabled in my kernel and I > try to run tcpdump on the interface I have logged in on via ssh (I'm not > really sure why it only happens in this case and in other cases). I run > "tcpdump -n -i sis0" and the panic as shown below. I do not have any > MAC policies loaded. > > The problem is (if I understand the code correctly) that MAC calls > BPFD_LOCK_ASSERT, which rwatson added NET_ASSERT_GIANT to, but since the > sis interrupt handler is marked INTR_MPSAFE then GIANT isn't aquired > before bpf_mtap (and therefor mac_check_bpfdesc_receive) is called. > > I'm not really sure what the correct fix is, but if bpf is locked, is > GIANT really required for it? Are you running a main line kernel with debug.mpsafenet turned on? Robert N M Watson FreeBSD Core Team, TrustedBSD Projects robert@fledge.watson.org Senior Research Scientist, McAfee Research > > panic: mutex Giant not owned at /data/nanobsd/src/sys/security/mac/mac_net.c:355 > at line 729 in file /data/nanobsd/src/sys/kern/kern_mutex.c > Debugger("panic") > Stopped at Debugger+0x45: xchgl %ebx,in_Debugger.0 > db> trace > Debugger(c063705f) at Debugger+0x45 > __panic(c06363ea,2d9,c063655f,c063669a,c0646fff) at __panic+0xc7 > _mtx_assert(c0689720,1,c0646fff,163) at _mtx_assert+0xc2 > mac_check_bpfdesc_receive(c1995c00,c1750c00) at mac_check_bpfdesc_receive+0x40 > bpf_mtap(c17536c0,c0adfa00) at bpf_mtap+0xa6 > sis_start(c1750c00) at sis_start+0x1a7 > sis_tick(c1750c00) at sis_tick+0x70 > softclock(0) at softclock+0x176 > ithread_loop(c0ac2500,c80c2d48,c0ac2500,c04c2e80,0) at ithread_loop+0x11c > fork_exit(c04c2e80,c0ac2500,c80c2d48) at fork_exit+0xa8 > fork_trampoline() at fork_trampoline+0x8 > --- trap 0x1, eip = 0, esp = 0xc80c2d7c, ebp = 0 --- > > -- > Simon L. Nielsen > FreeBSD Documentation Team >