kern/132734: panic in net/if_mib.c

Alexey Illarionov littlesavage at
Tue Mar 17 10:20:06 PDT 2009

>Number:         132734
>Category:       kern
>Synopsis:       panic in net/if_mib.c
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Mar 17 17:20:05 UTC 2009
>Originator:     Alexey Illarionov
>Release:        7.1-STABLE Mar  8 2009
FreeBSD 7.1-STABLE FreeBSD 7.1-STABLE #11: Sun Mar  8 22:25:30 MSK 2009 littlesavage at  i386
bsnmd(8) with mibII module on a machine with many dynamic interfaces can lead to panic in net/if_mib.c

I have mpd5 with about 600 active pptp tunnel interfaces.

kernel dump:
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Unread portion of the kernel message buffer:

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address	= 0x68
fault code		= supervisor read, page not present
instruction pointer	= 0x20:0xc06dcaf6
stack pointer	        = 0x28:0xe64c3aac
frame pointer	        = 0x28:0xe64c3b54
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, def32 1, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 27218 (bsnmpd)
trap number		= 12
panic: page fault
cpuid = 0
KDB: stack backtrace:
db_trace_self_wrapper(c09053a2,e64c3948,c063c0c9,c09217df,0,...) at db_trace_self_wrapper+0x26
kdb_backtrace(c09217df,0,c08e5975,e64c3954,0,...) at kdb_backtrace+0x29
panic(c08e5975,c0922ab1,c5fa34dc,1,1,...) at panic+0x119
trap_fatal(c3fc484c,0,1,0,c09fc4c4,...) at trap_fatal+0x333
trap_pfault(c0a039ec,e64c39f4,c0895295,c09fbe80,c,...) at trap_pfault+0x250
trap(e64c3a6c) at trap+0x3c2
calltrap() at calltrap+0x6
--- trap 0xc, eip = 0xc06dcaf6, esp = 0xe64c3aac, ebp = 0xe64c3b54 ---
sysctl_ifdata(c09bbfe0,e64c3c24,2,e64c3ba4,e64c3ba4,...) at sysctl_ifdata+0x196
sysctl_root(e64c3ba4,e64c3bb0,4,c44cd8c0,c4c7b688,...) at sysctl_root+0x127
userland_sysctl(c44cd8c0,e64c3c14,6,0,bfbf8208,...) at userland_sysctl+0x134
__sysctl(c44cd8c0,e64c3cfc,18,6,c065b6ab,...) at __sysctl+0xde
syscall(e64c3d38) at syscall+0x335
Xint0x80_syscall() at Xint0x80_syscall+0x20
--- syscall (202, FreeBSD ELF32, __sysctl), eip = 0x281871ef, esp = 0xbfbf7cfc, ebp = 0xbfbf7d28 ---
Uptime: 8d11h14m12s
Physical memory: 1012 MB
Dumping 282 MB: 267 251 235 219 203 187 171 155 139 123 107 91 75 59 43 27 11

Reading symbols from /boot/kernel/ichwd.ko...Reading symbols from /boot/kernel/ichwd.ko.symbols...done.
Loaded symbols for /boot/kernel/ichwd.ko
Reading symbols from /boot/modules/ng_ipacct.ko...done.
Loaded symbols for /boot/modules/ng_ipacct.ko
Reading symbols from /boot/kernel/ng_tee.ko...Reading symbols from /boot/kernel/ng_tee.ko.symbols...done.
Loaded symbols for /boot/kernel/ng_tee.ko
Reading symbols from /boot/kernel/nullfs.ko...Reading symbols from /boot/kernel/nullfs.ko.symbols...done.
Loaded symbols for /boot/kernel/nullfs.ko
#0  doadump () at pcpu.h:196
196	pcpu.h: No such file or directory.
	in pcpu.h

(kgdb) bt
#0  doadump () at pcpu.h:196
#1  0xc063be1c in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:418
#2  0xc063c102 in panic (fmt=Variable "fmt" is not available.
) at /usr/src/sys/kern/kern_shutdown.c:574
#3  0xc08a7673 in trap_fatal (frame=0xe64c3a6c, eva=104) at /usr/src/sys/i386/i386/trap.c:939
#4  0xc08a78d0 in trap_pfault (frame=0xe64c3a6c, usermode=0, eva=104) at /usr/src/sys/i386/i386/trap.c:852
#5  0xc08a82a2 in trap (frame=0xe64c3a6c) at /usr/src/sys/i386/i386/trap.c:530
#6  0xc088c90b in calltrap () at /usr/src/sys/i386/i386/exception.s:159
#7  0xc06dcaf6 in sysctl_ifdata (oidp=0xc09bbfe0, arg1=0xe64c3c24, arg2=2, req=0xe64c3ba4)
    at /usr/src/sys/net/if_mib.c:127
#8  0xc0645897 in sysctl_root (oidp=Variable "oidp" is not available.
) at /usr/src/sys/kern/kern_sysctl.c:1307
#9  0xc06459e4 in userland_sysctl (td=0xc44cd8c0, name=0xe64c3c14, namelen=6, old=0x0, oldlenp=0xbfbf8208, 
    inkernel=0, new=0x0, newlen=0, retval=0xe64c3c10, flags=0) at /usr/src/sys/kern/kern_sysctl.c:1402
#10 0xc064677e in __sysctl (td=0xc44cd8c0, uap=0xe64c3cfc) at /usr/src/sys/kern/kern_sysctl.c:1337
#11 0xc08a7c25 in syscall (frame=0xe64c3d38) at /usr/src/sys/i386/i386/trap.c:1090
#12 0xc088c970 in Xint0x80_syscall () at /usr/src/sys/i386/i386/exception.s:255
#13 0x00000033 in ?? ()
Previous frame inner to this frame (corrupt stack?)
(kgdb) up 7
#7  0xc06dcaf6 in sysctl_ifdata (oidp=0xc09bbfe0, arg1=0xe64c3c24, arg2=2, req=0xe64c3ba4)
    at /usr/src/sys/net/if_mib.c:127
127			ifp->if_snd.ifq_drops = ifmd.ifmd_snd_drops;

(kgdb) l
122			DONTCOPY(baudrate);
123	#undef DONTCOPY
124	#define COPY(fld) ifp->if_##fld = ifmd.ifmd_##fld
125			COPY(data);
126			ifp->if_snd.ifq_maxlen = ifmd.ifmd_snd_maxlen;
127			ifp->if_snd.ifq_drops = ifmd.ifmd_snd_drops;
128	#undef COPY
129			break;

(kgdb) p ifp
$1 = (struct ifnet *) 0x0
(kgdb) p *(int *)arg1
$4 = 332
(kgdb) p ifindex_table[332]
$12 = {ife_ifnet = 0x0, ife_dev = 0x0}




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