Re: [PATCH v3 1/4] rv/reactors: use context-sensitive lockdep wait type in rv_react()

Gabriele Monaco <[email protected]> writes:

> On Mon, 2026-08-10 at 01:10 +0800, [email protected] wrote:
>> From: Wen Yang <[email protected]>
>> 
>> Reactors must not explicitly take locks, so they should comply with
>> LD_WAIT_FREE.  However, reactor callbacks can run with preemption
>> enabled on any kernel (not just PREEMPT_RT).  If a timer interrupt
>> fires during the callback, the interrupt exit path schedules and
>> acquires rq->__lock (LD_WAIT_SPIN) while the lockdep override map that
>> declared LD_WAIT_FREE is still held, triggering a spurious
>> "Invalid wait context" warning:
...
> Anyway, I'd appreciate comments/acks from the other folks in the loop

Sorry, I do not know enough about lockdep to comment on this.

FWIW, I would rather just use LD_WAIT_SPIN and keep things
simple. Context-sensitive code paths "feels wrong" to me. Spinning
should either be allowed or forbidden. Making it dynamic "feels like" it
will bring further complications down the road.

But that's just my intuition.

Nam