Kernel panics on Leopard

Recently, since upgrading to OS X 10.5.3 it seems I’ve been experiencing some kernel panics, as much as once per day. After the last one I enabled kernel debug with the editing /Library/Preferences/SystemConfiguration/com.apple.Boot.plist and adding the following:

<key>Kernel Flags</key>
<string>-v debug=0×144</string> <—- ADD THIS

The -v flag is for verbose output during startup instead of the gray Apple screen. So once it kernel panicked again, it handily printed out the mac and IP address and stated it’s awaiting a remote debugger connection. On another Mac, download the 10.5.3 KernelDebugKit from ADC and fire up the debugger as follows:

gdb -arch i386 /Volumes/KernelDebugKit/mach_kernel

Then use gdb as follows:

(gdb) target remote-kdp
(gdb) attach 192.168.100.3
Connected.
(gdb) source /Volumes/KernelDebugKit/kgmacros
Loading Kernel GDB Macros package.  Type “help kgm” for more info.
(gdb) paniclog
panic(cpu 1 caller 0×002420F2): “ip_output: mix of packet in packetlist is wrong=0×577ab700″@/SourceCache/xnu/xnu-1228.5.18/bsd/netinet/ip_output.c:1494
Backtrace, Format – Frame : Return Address (4 potential args on stack)
0×5b7c7778 : 0×12b0fa (0×459294 0×5b7c77ac 0×133243 0×0)
0×5b7c77c8 : 0×2420f2 (0×475128 0×577ab700 0×0 0×0)
0×5b7c7918 : 0×24883c (0×577ab700 0×2 0×0 0×5fc9390)
0×5b7c7968 : 0×24a02b (0×2 0×0 0×0 0×1)
0×5b7c7a98 : 0×24732a (0×5fc9400 0×5b7c7c38 0×8e8544ca 0×364a8c0)
0×5b7c7c78 : 0×23bebd (0×57645f00 0×14 0xd7f47686 0×5358a4)
0×5b7c7cb8 : 0×23dc3f (0×57645f00 0×14 0×6 0×0)
0×5b7c7dd8 : 0×23dc7b (0×57645f00 0×0 0×6 0×21c5)
0×5b7c7df8 : 0×229bd3 (0×2 0×57645f00 0×5b7c7e48 0×141de3)
0×5b7c7e38 : 0×218be2 (0×2 0×57645f00 0×5b7c7e68 0×63a5fb58)
0×5b7c7ec8 : 0×215321 (0×671ae04 0×2 0×57645f00 0×3e95bc)
0×5b7c7ef8 : 0×215a7a (0×5278e4 0×5d71988 0×2 0×5b7c7f74)
0×5b7c7f68 : 0×215cd8 (0×0 0×57645f00 0×0 0×64f762c)
0×5b7c7fc8 : 0×19ebdc (0×64f7604 0×0 0×1a20b5 0×608e4f0)
Backtrace terminated-invalid frame pointer 0

BSD process name corresponding to current thread: kernel_task

Mac OS version:
9D34

Kernel version:
Darwin Kernel Version 9.3.0: Fri May 23 00:49:16 PDT 2008; root:xnu-1228.5.18~1/RELEASE_I386

I googled the output from the ip_output.c module and found several references, all indicating the Cisco VPN client’s kernel module and usually running a torrent client at the same time.

So for the moment I avoid using both at the same time and also removing the Cisco kernel modulel while not using the VPN:

[user@nefilim ~]$ sudo /System/Library/StartupItems/CiscoVPN/CiscoVPN stop
Stopping Cisco Systems VPN Driver
kextunload: unload kext /System/Library/Extensions/CiscoVPN.kext succeeded

So far so good. Sigh Cisco… won’t be the first time and certainly won’t be the last.