Date: Tue, 5 Jul 2011 10:09:00 GMT From: Mike Cui <cuicui@gmail.com> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/158665: kernel pagefault in in6_setscope() Message-ID: <201107051009.p65A90Zd004852@red.freebsd.org> Resent-Message-ID: <201107051010.p65AABTG043377@freefall.freebsd.org>
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>Number: 158665 >Category: kern >Synopsis: kernel pagefault in in6_setscope() >Confidential: no >Severity: critical >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Tue Jul 05 10:10:11 UTC 2011 >Closed-Date: >Last-Modified: >Originator: Mike Cui >Release: 8.2RELEASE >Organization: >Environment: FreeBSD router 8.2-RELEASE FreeBSD 8.2-RELEASE #3 >Description: When I set up a 6to4 tunnel device (stf0) and put it in output only mode according to man stf(4): # ifconfig ne0 inet 133.4.5.6 netmask 0xffffff00 # ifconfig stf0 inet6 2002:8504:0506:0000:a00:5aff:fe38:6f86 \ prefixlen 16 alias deprecated link0 # route add -inet6 2002:: -prefixlen 16 ::1 # route change -inet6 2002:: -prefixlen 16 ::1 -ifp stf0 The kernel often crashes sending traffic to other other 2002::/16 hosts. I think the problem is the "deprecated" address that's causing problems when trying to resolve ipv6 scope. The instruction causing the fault is: c069cee8: 0f b1 96 18 02 00 00 cmpxchg %edx,0x218(%esi) which I think corresponds to this line in the source: int in6_setscope(struct in6_addr *in6, struct ifnet *ifp, u_int32_t *ret_id) { int scope; u_int32_t zoneid = 0; struct scope6_id *sid; IF_AFDATA_LOCK(ifp); <----- HERE The fault virtual address is 0x218, which seems to suggest that ifp passed into this function is NULL. >How-To-Repeat: 1. On a machine with both a public IPv6 address (not 6to4 address) as well as IPv4, create a stf0 device and put it in "output only" mode according to man stf(4). 2. Ping another host using its 6to4 address (2002::/16). >Fix: >Release-Note: >Audit-Trail: >Unformatted:
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