Re: [PATCH v3 0/6] Static calls

[Jiri Kosina]

On Fri, 11 Jan 2019, hpa@xxxxxxxxx wrote:

> I still don't see why can't simply spin in the #BP handler until the 
> patch is complete.

I think this brings us to the already discussed possible deadlock, when 
one CPU#0 is in the middle of text_poke_bp(), CPU#1 is spinning inside 
spin_lock_irq*(&lock) and CPU#2 hits the breakpont while holding that very 
'lock'.

Then we're stuck forever, because CPU#1 will never handle the pending 
sync_core() IPI (it's not NMI).

Or have I misunderstood what you meant?

-- 
Jiri Kosina
SUSE Labs