Date: Thu, 7 Jun 2007 15:25:47 GMT From: Kena<kena@vodka-pomme.net> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/113457: Deadlock Message-ID: <200706071525.l57FPlOs094448@www.freebsd.org> Resent-Message-ID: <200706071530.l57FU2Qw090181@freefall.freebsd.org>
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>Number: 113457 >Category: kern >Synopsis: Deadlock >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Thu Jun 07 15:30:02 GMT 2007 >Closed-Date: >Last-Modified: >Originator: Kena >Release: 7.0-CURRENT >Organization: >Environment: FreeBSD fungus.kahlua 7.0-CURRENT FreeBSD 7.0-CURRENT #3: Fri Jun 1 10:49:34 CEST 2007 root@fungus.kahlua:/usr/obj/usr/src/sys/FUNGUS i386 >Description: Using a tunnel to access ipv6 (gw6c from www.go6.net): a deadlock occurs if the tunnel goes down while there are tcp6 connections opened. Sample panic report on this system: em0: watchdog timeout -- resetting Jun 7 10:17:21 fungus gw6c: Connection timeout occured. Jun 7 10:17:21 fungus gw6c: Disconnected. Retrying in 30 seconds. em0: watchdog timeout -- resetting lock order reversal: 1st 0xc30630d8 rtentry (rtentry) @ /usr/src/sys/netinet6/nd6.c:1963 2nd 0xc2ed977c radix node head (radix node head) @ /usr/src/sys/net/route.c:147 KDB: stack backtrace db_trace_self_wrapper(....) at db_trace_self_wrapper+0x26 kdb_backtrace(...) at kbd_backtrace+0x29 witness_checkorder(...) at witness_checkorder+0x6b7 _mtx_lock_flags(...) at _mtx_lock_flags+0xb0 rtalloc1(...) at rtalloc1+0x60 nd6_lookup(...) at nd6_loockup+0x55 nd6_is_addr_neighbor(...) at nd6_is_addr_neighbor+0x37 nd6_output(...) at nd6_output+0x10d ip6_output(...) at ip6_output+0x108a tcp_output(...) at tcp_output+0x12b3 tcp_timer(...) at tcp_timer+0x2ad softclock(...) at softclock+0x293 ithread_loop(...) at ithread_loop+0x1a8 fork_exit(...) at fork_exit+0xed fork_trampoline() at fork_trampoline+0x8 --- trap 0, eip = 0, esp = 0xd3c81d70, ebp = 0 --- panic: _mtx_lock_sleep: recursed on non-recursive mutex rtentry @ /usr/src/sys/net/route.c:197 cpuid = 0 KBD: enter: panic [thread pid 11 tid 100004 ] Stopped at kbd_enter+0x32: leave db> Configuration for kernel "FUNGUS" is GENERIC from 7.0-CURRENT with cpu I486_CPU and I586_CPU disabled. >How-To-Repeat: 1. set up a ip6 link with gw6c (from www.go6.net), "router" mode 2. open a tcp6 connection (for example irssi -c ipv6.chat.freenode.net) 3. break the network link (pull ethernet cable) 4. wait for gw6c to timeout A few seconds after gw6c reports the disconnect on the console the panic occurs. Crash 100% reproducible. >Fix: >Release-Note: >Audit-Trail: >Unformatted:
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