Linux Kernel crash mutex_lock_slowpath "blocked for more than 120 seconds". What to do?

Are you using an SSD drive by any chance?

I've seen these errors on my Ubuntu 10.10 system. What would happen was that there would be a SATA glitch that would completely mess up the disk subsystem. Subsequent attempts at disk I/O would result in 120-second timeouts similar to yours (the stack trace varied.)

I've documented the original problem here: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/707583

The (somewhat lame) question I asked about the timeouts is here: Mystery stack traces in /var/log/messages

I was using a P55-based motherboard and Crucial SSD drives. However, I've seen this reported with other chipsets, other makes of SSD drives, and other Linux kernels.

As far as I can tell, the only thing in common was the use of SSD drives.