Re: [PATCH] sched_ext: Use READ_ONCE() for the read side of dsq->seq update

[David CARLIER]

I missed that both reads are under dsq->lock ...  it was a wrong
analysis on my part. Sorry for the noise.

On Sun, 8 Mar 2026 at 00:17, Tejun Heo <tj@xxxxxxxxxx> wrote:
>
> On Sat, Mar 07, 2026 at 11:32:04PM +0000, David Carlier wrote:
> > -     WRITE_ONCE(dsq->seq, dsq->seq + 1);
> > -     p->scx.dsq_seq = dsq->seq;
> > +     nseq = READ_ONCE(dsq->seq) + 1;
> > +     WRITE_ONCE(dsq->seq, nseq);
> > +     p->scx.dsq_seq = nseq;
>
> Does this actually trigger KCSAN or wsa this just generated by AI? dsq->seq
> is protected by dsq lock. I don't see how dsq->seq load can become a racy
> read.
>
> --
> tejun