misc/123890: Crash & reboot on work with PPP low-speed connection

[Phil]

>Number:         123890
>Category:       misc
>Synopsis:       Crash & reboot on work with PPP low-speed connection
>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:   Thu May 22 10:30:04 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     Phil
>Release:        FreeBSD 7.0 RELEASE
>Organization:
>Environment:
FreeBSD x.y.ru 7.0-RELEASE FreeBSD 7.0-RELEASE #0: Wed Apr  9 16:26:04 VOLST 2008     phil at x.y.ru:/usr/obj/usr/src/sys/P1  i386

>Description:
I have gate with NAT to Internet, Squid-proxy, IPFW, Apache.
At me low-speed the allocated modem connection to a network. 
The system is reloaded at the big number of references (simultaneous work of 10 users) to a network.

Modem Courier 35.6

Debug on the crash.
kgdb:

Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0x7
fault code              = supervisor write, page not present
instruction pointer     = 0x20:0xc078d464
stack pointer           = 0x28:0xcd04b9f8
frame pointer           = 0x28:0xcd04ba08
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         = 865 (natd)
trap number             = 12
panic: page fault
Uptime: 1h35m29s
Physical memory: 243 MB
Dumping 42 MB: 27 11

#0  doadump () at pcpu.h:195
195     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) bt
#0  doadump () at pcpu.h:195
#1  0xc0746e23 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:409
#2  0xc074701f in panic (fmt=Variable "fmt" is not available.
) at /usr/src/sys/kern/kern_shutdown.c:563
#3  0xc0a2808c in trap_fatal (frame=0xcd04b9b8, eva=7) at /usr/src/sys/i386/i386/trap.c:899
#4  0xc0a28310 in trap_pfault (frame=0xcd04b9b8, usermode=0, eva=7) at /usr/src/sys/i386/i386/trap.c:812
#5  0xc0a28c99 in trap (frame=0xcd04b9b8) at /usr/src/sys/i386/i386/trap.c:490
#6  0xc0a1665b in calltrap () at /usr/src/sys/i386/i386/exception.s:139
#7  0xc078d464 in putc (chr=146, clistp=0xc220bc38) at /usr/src/sys/kern/tty_subr.c:416
#8  0xc23cfb9e in ?? ()
#9  0x00000092 in ?? ()
#10 0xc220bc38 in ?? ()
#11 0xc220bc38 in ?? ()
#12 0x00000000 in ?? ()
#13 0xcd04ba48 in ?? ()
#14 0xc220bc38 in ?? ()
#15 0xc220bc38 in ?? ()
#16 0xcd04ba48 in ?? ()
#17 0x0000e96d in ?? ()
#18 0xc220bc00 in ?? ()
#19 0xc22ce300 in ?? ()
#20 0x00000000 in ?? ()
#21 0xcd04ba49 in ?? ()
#22 0xcd04ba4a in ?? ()
#23 0x007e1692 in ?? ()
#24 0x00000000 in ?? ()
#25 0xc22ce300 in ?? ()
#26 0xc21cb4f4 in ?? ()
#27 0xc236b000 in ?? ()
#28 0xcd04ba98 in ?? ()
#29 0xc23ce12a in ?? ()
#30 0xc236b000 in ?? ()
#31 0x00000000 in ?? ()
#32 0xc23d33a0 in ?? ()
#33 0x000003df in ?? ()
#34 0xc21cb508 in ?? ()
#35 0x00000034 in ?? ()
#36 0x00000021 in ?? ()
#37 0x000000ff in ?? ()
#38 0x00000003 in ?? ()
#39 0x00000000 in ?? ()
#40 0x00000001 in ?? ()
#41 0xc21cb400 in ?? ()
#42 0xc22ce380 in ?? ()
#43 0xcd04bb10 in ?? ()
#44 0xc08281c9 in ip_output (m=0xc236b000, opt=0x0, ro=0xc23d33a0, flags=Variable "flags" is not available.
) at /usr/src/sys/netinet/ip_output.c:549
Previous frame inner to this frame (corrupt stack?)

(kgdb) bt full
#0  doadump () at pcpu.h:195
No locals.
#1  0xc0746e23 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:409
        _giantcnt = Variable "_giantcnt" is not available.

>How-To-Repeat:
2 - 5 incident per day
>Fix:


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