Re: kern/51467: detaching USB network interface panics

[Ryota Ozaki <ozaki-r%netbsd.org@localhost>]

The following reply was made to PR kern/51467; it has been noted by GNATS.

From: Ryota Ozaki <ozaki-r%netbsd.org@localhost>
To: "gnats-bugs%NetBSD.org@localhost" <gnats-bugs%netbsd.org@localhost>
Cc: kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/51467: detaching USB network interface panics
Date: Mon, 12 Sep 2016 12:59:59 +0900

 On Mon, Sep 12, 2016 at 12:15 AM,  <mlelstv%serpens.de@localhost> wrote:
 >>Number:         51467
 >>Category:       kern
 >>Synopsis:       detaching USB network interface panics
 >>Confidential:   no
 >>Severity:       critical
 >>Priority:       medium
 >>Responsible:    kern-bug-people
 >>State:          open
 >>Class:          sw-bug
 >>Submitter-Id:   net
 >>Arrival-Date:   Sun Sep 11 15:15:00 +0000 2016
 >>Originator:     Michael van Elst
 >>Release:        NetBSD 7.99.36
 >>Organization:
 >
 >>Environment:
 >
 >
 > System: NetBSD tazz 7.99.36 NetBSD 7.99.36 (TAZZ) #7: Sun Sep 11 16:12:19 CEST 2016 mlelstv@gossam:/home/netbsd-current/obj.amd64/home/netbsd-current/src/sys/arch/amd64/compile/TAZZ amd64
 > Architecture: x86_64
 > Machine: amd64
 >>Description:
 > Detaching a configured run(4) interface resulted in a panic.
 >
 > DDB shows:
 >
 > find_pfxlist_reachable_router.isra.6() at find_pfxlist_reachable_router.isra.6+0x11
 > pfxlist_onlink_check() at pfxlist_onlink_check+0x132
 > nd6_purge() at nd6_purge+0x103
 > in6_ifdetach() at in6_ifdetach+0x1b
 > udp6_purgeif_wrapper() at udp6_purgeif_wrapper+0x39
 > if_detach() at if_detach+0x264
 > run_detach() at run_detach+0x75
 > config_detach() at config_detach+0xf8
 > usb_disconnect_port() at usb_disconnect_port+0x18b
 > uhub_explore() at uhub_explore+0x1fe
 > uhub_explore() at uhub_explore+0xac
 > usb_discover() at usb_discover+0x6f
 > usb_event_thread() at usb_event_thread+0x238
 >
 > GDB shows more detail:
 >
 > #8  0xffffffff80566be7 in find_pfxlist_reachable_router (pr=<optimized out>)
 >     at /home/netbsd-current/src/sys/netinet6/nd6_rtr.c:1416
 > #9  0xffffffff80567a07 in pfxlist_onlink_check () at /home/netbsd-current/src/sys/netinet6/nd6_rtr.c:1576
 > #10 0xffffffff8056800c in prelist_remove (pr=<optimized out>)
 >     at /home/netbsd-current/src/sys/netinet6/nd6_rtr.c:1058
 > #11 0xffffffff805610d6 in nd6_purge (ifp=ifp@entry=0xffff8000070f3008, ext=0xfffffe811e16aab8, ext@entry=0x0)
 >     at /home/netbsd-current/src/sys/netinet6/nd6.c:866
 > #12 0xffffffff8054cf7f in in6_ifdetach (ifp=ifp@entry=0xffff8000070f3008)
 >     at /home/netbsd-current/src/sys/netinet6/in6_ifattach.c:815
 >
 >    0xffffffff80566bd6 <find_pfxlist_reachable_router>:  push   %rbp
 >    0xffffffff80566bd7 <find_pfxlist_reachable_router+1>:        mov    %rsp,%rbp
 >    0xffffffff80566bda <find_pfxlist_reachable_router+4>:        push   %rbx
 >    0xffffffff80566bdb <find_pfxlist_reachable_router+5>:        sub    $0x8,%rsp
 >    0xffffffff80566bdf <find_pfxlist_reachable_router+9>:        mov    %rdi,%rbx
 >    0xffffffff80566be2 <find_pfxlist_reachable_router+12>:       test   %rdi,%rdi
 >    0xffffffff80566be5 <find_pfxlist_reachable_router+15>:       je     0xffffffff80566c38 <find_pfxlist_reachable_router+98>
 > => 0xffffffff80566be7 <find_pfxlist_reachable_router+17>:       mov    0x10(%rbx),%rdi
 >    0xffffffff80566beb <find_pfxlist_reachable_router+21>:       mov    0x30(%rdi),%rsi
 >    0xffffffff80566bef <find_pfxlist_reachable_router+25>:       testb  $0x1,0x4c(%rsi)
 >
 > rbx            0x2587e94bac0e70d2       2704386612477718738
 >
 > which is garbage.
 >
 >
 >>How-To-Repeat:
 > Detach a USB network interface that has IPv6 configured.
 
 Do you know when it worked lastly?
 
 If degraded by recent changes, one suspect is a change at 8/16(*).
 Then could you try a kernel at 8/15?
 
 (*) http://www.nerv.org/netbsd/?q=id:20160816T103157Z.479577018086b726daa7c1600fe5219e96a677d6
 
   ozaki-r