Re: panic: sleeping thread & bufwrite: buffer is not busy???

On Fri, 12 Dec 2008, Bartosz Stec wrote:

> OK. I'll try to build debug kernel today and I will provide backtrace. I 
> forgot to mention in my last post that I saw very similiar (if not 
> identical) lines to:
>
>   Sleeping thread (tid 100054, pid 646) owns a non-sleepable lock
>   panic: sleeping thread
>   panic: bufwrite: buffer is not busy???
>
> while checking dmesg buffer after one of the panics earlier. That's why I 
> assumed it's probably the same issue. Sorry for confusion, they're my first 
> steps with CURRENT and very first experience with kernel panic :).

Yeah, secondary panics can significantly complicate the debugging process, 
unfortunately.  Another similar class of confusing cases exist when panics 
occur and are then preempted during the panic by another thread that promptly 
trips over state left behind by the first thread, and panics. :-)

Robert N M Watson
Computer Laboratory
University of Cambridge