Date: Wed, 10 Nov 2004 16:43:04 +0100 From: Arjan Van Leeuwen <avleeuwen@gmail.com> To: Robert Watson <rwatson@freebsd.org> Cc: freebsd-stable@freebsd.org Subject: Re: Panic in 5.3, related to network traffic Message-ID: <d86b4873041110074341796537@mail.gmail.com> In-Reply-To: <Pine.NEB.3.96L.1041110100538.60848V-100000@fledge.watson.org> References: <d86b4873041109171077239269@mail.gmail.com> <Pine.NEB.3.96L.1041110100538.60848V-100000@fledge.watson.org>
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On Wed, 10 Nov 2004 10:15:31 +0000 (GMT), Robert Watson <rwatson@freebsd.org> wrote: > > Could you recompile your kernel with "options INVARIANTS"? It looks like > whatever is happening should be triggering one of the assertions in > m_copydata(), if not icmp_error(), and it would be helpful to track it a > little earlier before it faults. It looks like m_copydata() is alking off > of the end of an mbuf chain, since min()'s only pointer dereference is to > get the length out of an mbuf. However, under those circumstances it > shouldn't need to walk a chain. > > Another thing we may want to do for debugging purposes, subject to this > being something you can put the system through, is add an additional > warning in icmp_error() if the mbuf comes in fragmented. Something like > the following would generate a warning instead of panicking: > (...) I've applied the patch and enabled INVARIANTS. The result was that I did indeed see the warning once, but _not_ when I was trying to create a panic; I saw the warning shortly after starting the machine, I didn't yet start emule to get the panic. When I did start emule, I got a panic that looked a bit different. In this screenshot, you can see both the warning message (that appeared a lot earlier, independent of the panic) and the new panic: http://www.piwebs.com/freebsd/panic.jpg Here is what addr2line tells me: winston% addr2line -f -e kernel.debug.20041110 0xC074CF44 uma_dbg_free /usr/src/sys/vm/uma_dbg.c:308 winston% addr2line -f -e kernel.debug.20041110 0xC074BD13 uma_zfree_arg /usr/src/sys/vm/uma_core.c:2237 winston% addr2line -f -e kernel.debug.20041110 0xC0646C9A m_freem /usr/src/sys/vm/uma.h:302 winston% addr2line -f -e kernel.debug.20041110 0xC0460D11 fr_check /usr/src/sys/contrib/ipfilter/netinet/fil.c:1402 winston% addr2line -f -e kernel.debug.20041110 0xC0462052 fr_check_wrapper /usr/src/sys/contrib/ipfilter/netinet/ip_fil.c:344 winston% addr2line -f -e kernel.debug.20041110 0xC067F11D pfil_run_hooks /usr/src/sys/net/pfil.c:137 winston% addr2line -f -e kernel.debug.20041110 0xC069BE95 ip_input /usr/src/sys/netinet/ip_input.c:439 winston% addr2line -f -e kernel.debug.20041110 0xC067DB92 netisr_processqueue /usr/src/sys/net/netisr.c:229 winston% addr2line -f -e kernel.debug.20041110 0xC067DD76 swi_net /usr/src/sys/net/netisr.c:346 winston% addr2line -f -e kernel.debug.20041110 0xC06051C4 ithread_loop /usr/src/sys/kern/kern_intr.c:548 Thanks for your help, Arjan
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