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SubjectRe: BUG: ib_mad ftrace event unsupported migration
On Wed, 2 Nov 2022 14:02:49 +0000
Leonid Ravich <leonid.ravich@toganetworks.com> 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

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