Re: BUG: ib_mad ftrace event unsupported migration

[Steven Rostedt]

On Wed, 2 Nov 2022 14:02:49 +0000
Leonid Ravich <leonid.ravich@xxxxxxxxxxxxxxxx> wrote:

> >I'm guessing some driver's query_pkey op, but AFAIK we don't have any
> >explicit pre-emption reenablements in the code - unless it is sneaky..  
> trace infra uses preempt_disable_notrace/preempt_enable_notrace  to disable/enable preemtion but  my kernel compiled without CONFIG_PREEMPTION so this functions are only barriers - looks like the idea behind was to avoid involuntary preemtion  but in our case it is a voluntary (there is a wait_for_completion in the query_pkey  rabbit hole).
> 
> so no scheduler here to warn about illegal migration. 

Well, you should be testing under different configs ;-)

It would have given you the reason for the real bug.

-- Steve