On Sun, 26 May 2019, Pavel Machek wrote: > On Sat 2019-05-25 10:32:31, Hugh Dickins wrote: > > > > Thanks, Pavel: yes, that works fine for me on the T420s, no debug > > complaints, good and silent; and the wifi LED is blinking as before. > > I'd like to prevent recurrence of similar problem, and I wonder if you > can give me a hint. > > I can annotate code that can sleep with might_sleep(). > > How can I annotate code that can not sleep? I might do > > spin_lock(&dummy); > this_should_not_sleep(); > spin_unlock(&dummy); > > But I don't really need extra serialization. I just want annotations for > lockdep. Any ideas? I haven't tried to do that directly, so I'm likely to give bad advice: in particular, I forget the limitations of checking in_atomic(). But very useful (and much cheaper than lockdep) debug options in this area are CONFIG_DEBUG_PREEMPT and CONFIG_DEBUG_ATOMIC_SLEEP. Hugh
