Firewire-driven Kernal Panics

[rev316]

Hola,

I think I've may discovered a bug within 10.4.9. So please chime in if you have experienced it. After some googling, I found some unanswered topics about other users having same if not similar issues with Mac OS X's IOFamily. During the end of sleeping (upon waking), if I unplug my external drive (without ejecting), and plug my ipod in... Kaboom. Though, this has been hard to replicate because it seems to only work when you get the iPod in at the right moment. A simple backtrace of the log's dependencies shows both:

dependency: com.apple.iokit.IOPCIFamily(2.2)@0x582000
dependency: com.apple.iokit.IOFireWireFamily(2.5.5)@0x7ef000

Isn't a huge issue, but annoying sometimes when I forget. Any thoughts?

-Rev316

 

[mad jew]

Just for clarification, the external drive is connected via Firewire but the iPod is connected via USB? Also, technically it's not a bug because the user should eject a disk before disconnecting it.

 

[rev316]

Good point, but you would think OS X would just handle it differently. Other then panic....

And the iPod is also firewire. It's when I unplug the external drive (without ejecting-in waking up) and then plugging in the firewire iPod.

Is this more common then I think?

 

[ElectricSheep]

Throwing a kernel panic probably isn't the most elegant way of handling the situation you are describing, but you are swapping out firewire devices when the operating system is still waking up. Since the kernel hasn't been notified of this change, your system reaches an unstable state. When that happens, the kernel panics to prevent serious damage to your data or hardware. Its not elegant, but its a lot better than nuking your hard drive or iPod.

Firewire storage devices are memory-mapped when they are connected. If you are busy unplugging and plugging fireiwire devices while the operating system is still waking, you are begging for information loss/corruption. You need to unmount these devices before unplugging them.

 

[rev316]

Thanks ElectricSheep,

Great post. Much appreciated!