kern/140634: destroying if_lagg interface with if_vlan members causing 100% usage by ifconfig

Tue Nov 17 09:00:13 UTC 2009

>Number:         140634
>Category:       kern
>Synopsis:       destroying if_lagg interface with if_vlan members causing 100% usage by ifconfig
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Nov 17 09:00:11 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Dmitriy
>Release:        7.2-RELEASE
>Organization:
NetLine NSP
>Environment:
FreeBSD bras2.domain.ru 7.2-RELEASE FreeBSD 7.2-RELEASE #4: Sun Nov 15 03:53:05 YEKT 2009     dm at bras2.domain.ru:/mnt/sources/src-7.2/sys/i386/compile/BRAS2  i386
>Description:
I use if_vlan over if_lagg over some if_em's.
If i need to delete interfaces cloning by 
/etc/rc.d/netif clonedown
i got 100% usage by "ifconfig lagg0 destroy"

If delete vlan's from lagg0 first, 
"ifconfig lagg0 destroy" works properly.

I build kernel with INVARIANTs and WITNESS and got panic:
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Unread portion of the kernel message buffer:
<5>lagg0: link state changed to DOWN
<5>em1: link state changed to DOWN
<5>vlan100: link state changed to DOWN
<5>vlan8: link state changed to DOWN
panic: if_delmulti: ifnet went away
cpuid = 0
KDB: enter: panic
Physical memory: 1012 MB
Dumping 69 MB: 54 38 22 6

Reading symbols from /boot/kernel/coretemp.ko...Reading symbols from /boot/kernel/coretemp.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/coretemp.ko
Reading symbols from /boot/kernel/if_em_yandex_696.ko...Reading symbols from /boot/kernel/if_em_yandex_696.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/if_em_yandex_696.ko
Reading symbols from /boot/kernel/acpi.ko...Reading symbols from /boot/kernel/acpi.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/acpi.ko
#0  doadump () at pcpu.h:196
196             __asm __volatile("movl %%fs:0,%0" : "=r" (td));
(kgdb) bt
#0  doadump () at pcpu.h:196
#1  0xc044c419 in db_fncall (dummy1=-1066288168, dummy2=0, dummy3=-1,
    dummy4=0xf9a7076c "") at ../../../ddb/db_command.c:516
#2  0xc044c9cf in db_command (last_cmdp=0xc0792c74, cmd_table=0x0, dopager=0)
    at ../../../ddb/db_command.c:413
#3  0xc044ca44 in db_command_script (command=0xc0793b8c "call doadump")
    at ../../../ddb/db_command.c:484
#4  0xc04502b0 in db_script_exec (scriptname=0xf9a70878 "kdb.enter.panic",
    warnifnotfound=Variable "warnifnotfound" is not available.
) at ../../../ddb/db_script.c:302
#5  0xc045038d in db_script_kdbenter (eventname=0xc072bdcd "panic")
    at ../../../ddb/db_script.c:324
#6  0xc044e298 in db_trap (type=3, code=0) at ../../../ddb/db_main.c:227
#7  0xc053fa56 in kdb_trap (type=3, code=0, tf=0xf9a709b0)
    at ../../../kern/subr_kdb.c:524
#8  0xc06e7e6f in trap (frame=0xf9a709b0) at ../../../i386/i386/trap.c:688
#9  0xc06cc78b in calltrap () at ../../../i386/i386/exception.s:159
#10 0xc053fbda in kdb_enter_why (why=0xc072bdcd "panic", msg=0xc072bdcd "panic")
    at cpufunc.h:60
#11 0xc05139c6 in panic (fmt=0xc0738ebf "%s: ifnet went away")
    at ../../../kern/kern_shutdown.c:557
#12 0xc05ac0b6 in if_delmulti (ifp=0xc47c7000, sa=0xf9a70a72) at ../../../net/if.c:2565
#13 0xc05b6960 in vlan_unconfig_locked (ifp=0xc45ea800) at ../../../net/if_vlan.c:1120
#14 0xc05b6e4f in vlan_ifdetach (arg=0x0, ifp=0xc47c7000) at ../../../net/if_vlan.c:497
#15 0xc05af87d in if_detach (ifp=0xc47c7000) at ../../../net/if.c:830
#16 0xc05b18fd in ether_ifdetach (ifp=0xc47c7000) at ../../../net/if_ethersubr.c:926
#17 0xc05b3982 in lagg_clone_destroy (ifp=0xc47c7000) at ../../../net/if_lagg.c:282
#18 0xc05b0a27 in ifc_simple_destroy (ifc=0xc07795c0, ifp=0xc47c7000)
    at ../../../net/if_clone.c:560
#19 0xc05b0d91 in if_clone_destroyif (ifc=0xc07795c0, ifp=0xc47c7000)
    at ../../../net/if_clone.c:218
#20 0xc05b136f in if_clone_destroy (name=0xc5d382a0 "lagg0")
    at ../../../net/if_clone.c:196
#21 0xc05affeb in ifioctl (so=0xc4899680, cmd=2149607801, data=0xc5d382a0 "lagg0",
    td=0xc47f2230) at ../../../net/if.c:1997
#22 0xc0557947 in soo_ioctl (fp=0xc5b54850, cmd=2149607801, data=0xc5d382a0,
    active_cred=0xc5b6c600, td=0xc47f2230) at ../../../kern/sys_socket.c:191
#23 0xc0551de3 in kern_ioctl (td=0xc47f2230, fd=3, com=2149607801,
    data=0xc5d382a0 "lagg0") at file.h:269
#24 0xc0551f44 in ioctl (td=0xc47f2230, uap=0xf9a70cfc)
    at ../../../kern/sys_generic.c:571
#25 0xc06e7643 in syscall (frame=0xf9a70d38) at ../../../i386/i386/trap.c:1090
#26 0xc06cc7f0 in Xint0x80_syscall () at ../../../i386/i386/exception.s:255
#27 0x00000033 in ?? ()
Previous frame inner to this frame (corrupt stack?)
>How-To-Repeat:
ifconfig lagg0 create
ifconfig vlan100 create
ifconfig vlan100 vlandev lagg0 vlan 100
ifconfig lagg0 destroy
>Fix:
maybe /etc/rc.d/netif script must delete all vlan members of existing if_lagg interfaces and then destroy if_lagg interfaces.

>Release-Note:
>Audit-Trail:
>Unformatted: