Re: Hard hang in hypervisor!?

Linas Vepstas wrote:

I was futzing with linux-2.6.23-rc8-mm1 in a power6 lpar when,
for whatever reason, a spinlock locked up. The bizarre thing 
was that the rest of system locked up as well: an ssh terminal,
and also an hvc console.

Breaking into the debugger showed 4 cpus, 1 of which was 
deadlocked in the spinlock, and the other 3 in 
.pseries_dedicated_idle_sleep

This was, ahhh, unexpected.  What's up with that? Can
anyone provide any insight?

Sounds consistent with a task trying to double-acquire the lock, or an
interrupt handler attempting to acquire a lock that the current task
holds.  Or maybe even an uninitialized spinlock.  Do you know which
lock it was?