On Sat, Sep 12, 2026 at 12:47 AM Paul E. McKenney <[email protected]> wrote:
>
> On Fri, Sep 11, 2026 at 05:35:15PM +0800, Kunwu Chan wrote:
> > Add the lockdep annotation, same-type SRCU nesting warning, and
> > early-boot check used by __synchronize_srcu().
> >
> > Suggested-by: Zqiang <[email protected]>
> > Signed-off-by: Kunwu Chan <[email protected]>
>
> Queued for review and testing, thank you both!
>
> Interestingly enough, it is now the case that there is a grace-period
> wait that can be placed in a normal RCU read-side critical section.
> Does this mean that we should also adjust the --do-srcu-lockdep testing
> in tools/testing/selftests/rcutorture/bin/torture.sh?

Thanks, Paul. Good point.

I’ll check the current `--do-srcu-lockdep` coverage, including the
case where `synchronize_srcu_atomic()` is called from a normal RCU
read-side critical section, and follow up with the necessary torture
testing changes.

Thanks,
Kunwu

>
>                                                         Thanx, Paul
>
> > ---
> >  kernel/rcu/srcutree.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
> > index 6a9c432a3bd0..6c729e805fb3 100644
> > --- a/kernel/rcu/srcutree.c
> > +++ b/kernel/rcu/srcutree.c
> > @@ -2123,6 +2123,14 @@ void synchronize_srcu_atomic(struct srcu_struct *ssp)
> >       unsigned long rdm0, rdm1;
> >       unsigned long unlocks0, unlocks1;
> >
> > +     srcu_lock_sync(&ssp->dep_map);
> > +
> > +     RCU_LOCKDEP_WARN(lockdep_is_held(ssp),
> > +                      "Illegal synchronize_srcu_atomic() in same-type SRCU 
> > read-side critical section");
> > +
> > +     if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
> > +             return;
> > +
> >       // Initialize.  Either init_srcu_struct() was invoked or
> >       // DEFINE_SRCU() or similar was used.  Therefore, no allocation
> >       // will be done here.
> > --
> > 2.43.0
> >

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