Re: perf: fuzzer BUG: KASAN: stack-out-of-bounds in __unwind_start

From: Paul E. McKenney
Date: Tue Nov 29 2016 - 10:10:29 EST

On Tue, Nov 29, 2016 at 01:43:23PM +0100, Peter Zijlstra wrote:
> On Mon, Nov 28, 2016 at 11:52:41PM -0600, Josh Poimboeuf wrote:
> > Did a little digging on git blame and found the following commit (which
> > seems to be the cause of the KASAN warning and missing stack dump):
> >
> > bc1dce514e9b ("rcu: Don't use NMIs to dump other CPUs' stacks")
> >
> > I presume this commit is still needed because of the NMI printk deadlock
> > issues which were discussed at Kernel Summit. I guess those issues need
> > to be sorted out before the above commit can be reverted.
> Also, I most always run with these here patches applied:
> People are very busy polishing the turd we call printk, but from where
> I'm sitting its terminally and unfixably broken.
> I should certainly add a revert of the above commit to the stack of
> patches I carry.

This isn't making me feel particularly confident about switching RCU
CPU stall warnings back to NMIs... ;-)

Thanx, Paul