Kernel panics with iBook G4 and 10.3.9 (modem kext)

Question

Upon upgrading my iBook G4 to 10.3.9, I began recieving a rash of kernel panics (about 1-2 a day) . This was quite a change from the relatively solid machine I had previous ( about a panic a month with 10.3.8 with heavy daily use ). I initially suspected some ram failure but after extensive testing (bit flip, pattern, etc.) in single user mode eliminated that possibility.
The panic log contiuously pointed at the MotorolaSM56K driver. I now suspected a kernel module/kernel incompatibility problem. After activating root and kextunloading that class I was able to regain some measure of stabilty ( about 4-5 days between crashes ). This stability varied as the class would be reloaded by OS under certain (unknown) conditions. As I have actually never used the built-in modem I have now decided to fully unload the AppleI2SModemFamily.kext extension, to avoid the SM56K class from starting.
Have others noticed similar issues when upgrading from 10.3.8 to 10.3.9? or with the modem kext? I am suprised at the poor quality of this "upgrade", having used X since 10.1 on my ibook G3 (that I have now kept at 10.3.8)
Is the modem kernel extension a red herring and its truly an issue in the kernel (that the modem extension exposes)?
attached are some snippets from my (now very long) panic.log:
Wed Nov 23 14:35:32 2005
Unresolved kernel trap(cpu 0): 0x300 - Data access DAR=0x000000000000025C PC=0x000000000008D810
Latest crash info for cpu 0:
Exception state (sv=0x326E3280)
PC=0x0008D810; MSR=0x00001030; DAR=0x0000025C; DSISR=0x40000000; LR=0x0001784C; R1=0x121EBC50; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x000177F4 0x00014774 0x000219F8 0x00040DC4 0x00016360 0x000189D4 0x0001C9E0 0x00027444
0x00094318 0x0079003E
Kernel loadable modules in backtrace (with dependencies):
com.apple.driver.MotorolaSM56K(1.3.1)@0x6ef000
dependency: com.apple.driver.AppleI2SModemFamily(1.1.2)@0x6e4000
dependency: com.apple.iokit.IOSerialFamily(6.0.1d20)@0x49d000
Proceeding back via exception chain:
Exception state (sv=0x326E3280)
previously dumped as "Latest" state. skipping...
Exception state (sv=0x259F4A00)
PC=0x900106D8; MSR=0x0000F030; DAR=0x1C348004; DSISR=0x40000000; LR=0x901D9778; R1=0xBFFFEDB0; XCP=0x00000030 (0xC00 - System call)
Kernel version:
Darwin Kernel Version 7.9.0:
Wed Mar 30 20:11:17 PST 2005; root:xnu/xnu-517.12.7.obj~1/RELEASE_PPC
panic(cpu 0): 0x300 - Data access
Latest stack backtrace for cpu 0:
Backtrace:
0x00083498 0x0008397C 0x0001EDA4 0x00090C38 0x0009402C
Proceeding back via exception chain:
Exception state (sv=0x326E3280)
PC=0x0008D810; MSR=0x00001030; DAR=0x0000025C; DSISR=0x40000000; LR=0x0001784C; R1=0x121EBC50; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x000177F4 0x00014774 0x000219F8 0x00040DC4 0x00016360 0x000189D4 0x0001C9E0 0x00027444
0x00094318 0x0079003E
Kernel loadable modules in backtrace (with dependencies):
com.apple.driver.MotorolaSM56K(1.3.1)@0x6ef000
dependency: com.apple.driver.AppleI2SModemFamily(1.1.2)@0x6e4000
dependency: com.apple.iokit.IOSerialFamily(6.0.1d20)@0x49d000
Exception state (sv=0x259F4A00)
PC=0x900106D8; MSR=0x0000F030; DAR=0x1C348004; DSISR=0x40000000; LR=0x901D9778; R1=0xBFFFEDB0; XCP=0x00000030 (0xC00 - System call)
Kernel version:
Darwin Kernel Version 7.9.0:
Wed Mar 30 20:11:17 PST 2005; root:xnu/xnu-517.12.7.obj~1/RELEASE_PPC
Wed Nov 23 20:54:17 2005
Unresolved kernel trap(cpu 0): 0x300 - Data access DAR=0x000000000000025C PC=0x000000000008D810
Latest crash info for cpu 0:
Exception state (sv=0x326E3280)
PC=0x0008D810; MSR=0x00001030; DAR=0x0000025C; DSISR=0x40000000; LR=0x0001784C; R1=0x121EBC50; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x000177F4 0x00014774 0x000219F8 0x00040DC4 0x00016360 0x000189D4 0x0001C9E0 0x00027444
0x00094318 0x0079003E
Kernel loadable modules in backtrace (with dependencies):
com.apple.driver.MotorolaSM56K(1.3.1)@0x6ef000
dependency: com.apple.driver.AppleI2SModemFamily(1.1.2)@0x6e4000
dependency: com.apple.iokit.IOSerialFamily(6.0.1d20)@0x49d000
Proceeding back via exception chain:
Exception state (sv=0x326E3280)
previously dumped as "Latest" state. skipping...
Exception state (sv=0x259F4A00)
PC=0x900106D8; MSR=0x0000F030; DAR=0x1C348004; DSISR=0x40000000; LR=0x901D9778; R1=0xBFFFEDB0; XCP=0x00000030 (0xC00 - System call)
Kernel version:
Darwin Kernel Version 7.9.0:
Wed Mar 30 20:11:17 PST 2005; root:xnu/xnu-517.12.7.obj~1/RELEASE_PPC
panic(cpu 0): 0x300 - Data access
Latest stack backtrace for cpu 0:
Backtrace:
0x00083498 0x0008397C 0x0001EDA4 0x00090C38 0x0009402C
Proceeding back via exception chain:
Exception state (sv=0x326E3280)
PC=0x0008D810; MSR=0x00001030; DAR=0x0000025C; DSISR=0x40000000; LR=0x0001784C; R1=0x121EBC50; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x000177F4 0x00014774 0x000219F8 0x00040DC4 0x00016360 0x000189D4 0x0001C9E0 0x00027444
0x00094318 0x0079003E
Kernel loadable modules in backtrace (with dependencies):
com.apple.driver.MotorolaSM56K(1.3.1)@0x6ef000
dependency: com.apple.driver.AppleI2SModemFamily(1.1.2)@0x6e4000
dependency: com.apple.iokit.IOSerialFamily(6.0.1d20)@0x49d000
Exception state (sv=0x259F4A00)
PC=0x900106D8; MSR=0x0000F030; DAR=0x1C348004; DSISR=0x40000000; LR=0x901D9778; R1=0xBFFFEDB0; XCP=0x00000030 (0xC00 - System call)
Kernel version:
Darwin Kernel Version 7.9.0:
Wed Mar 30 20:11:17 PST 2005; root:xnu/xnu-517.12.7.obj~1/RELEASE_PPC
iBook G4   Mac OS X (10.3.9)  

Answer 1

A reasonable possibility is that you upgraded without
first repairing the hard drive and permissions.
Although this may not help after the fact, I suggest
you give it a try:
Boot from your OS X Installer. Be sure to use the
installer for the version of OS X you have installed.
After the installer loads select Disk Utility from
the Installer menu (or Utilities menu if using
Tiger.) After DU loads select your OS X volume from
the list on the left, click on the First Aid tab,
then click on the Repair Disk button. If DU reports
any errors that have been fixed, then re-run Repair
Disk until no errors are reported. If no errors are
reported click on the Repair Permissions button. Wait
until the operation completes, then quit DU and
return to the installer. Now shutdown the computer
for a couple of minutes and then restart normally.
This I did yesterday and found a slew of permission setting problems - speaking to some endemic issues in the OS software/installation scripts. But after doing this repair (all were repairable) and reinstalling the COMBO update to 10.3.9 the problem persists. Thanks for the tip.
Keep in mind that RAM can pass the memory tests yet
not work properly with OS X. Therefore, you cannot
assume that because the RAM passed the memory tests
that it is fully functional with OS X. If you have
installed third-party RAM, the only definitive test
is to remove it and see if the kernel panics cease.
If they do, then add one module at a time and
re-test. When the panics recur you have identified
the faulty module.
Though I find disconcerting that Apple's POST routines are not sufficient to identify out of spec/incompatible RAM, I fully tested my memory (as mentioned) using memtest in single user mode. Memtest is a gnu program ported over from BSD unix that does exhaustive memory testing (ie the patterns, walking, etc that I mentioned)
Of course it's also possible there is a hardware
problem with the modem itself or that your upgrade to
10.3.9 is defective. After repairing the hard drive
and permissions you should reinstall the 10.3.9
update, but be sure to do so using the Combo updater.
You can download it from Apple's download site.
How the modem hardware failure mysteriously coincided with my 10.3.9 upgrade begs the question on how could be anything but a software issue...