On Wed, Apr 10, 2024 at 4:05 AM Paul E. McKenney <paulmck@kernel.org> wrote:
>
> On Sun, Apr 07, 2024 at 07:27:14PM +0800, Zqiang wrote:
> > This commit also allows rcutorture to support srcu double call test
> > with CONFIG_DEBUG_OBJECTS_RCU_HEAD option enabled. the non-raw sdp
> > structure's->spinlock will be acquired in call_srcu(), in Preempt-RT
> > kernels, this spinlock is sleepable, therefore remove disable-irq and
> > disable-preempt protection.
> >
> > Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
> > ---
> >  kernel/rcu/rcutorture.c | 46 +++++++++++++++++++++++------------------
> >  1 file changed, 26 insertions(+), 20 deletions(-)
> >
> > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> > index 807fbf6123a7..44cc455e1b61 100644
> > --- a/kernel/rcu/rcutorture.c
> > +++ b/kernel/rcu/rcutorture.c
> > @@ -390,6 +390,7 @@ struct rcu_torture_ops {
> >       int extendables;
> >       int slow_gps;
> >       int no_pi_lock;
> > +     int debug_objects;
> >       const char *name;
> >  };
> >
> > @@ -577,6 +578,7 @@ static struct rcu_torture_ops rcu_ops = {
> >       .irq_capable            = 1,
> >       .can_boost              = IS_ENABLED(CONFIG_RCU_BOOST),
> >       .extendables            = RCUTORTURE_MAX_EXTEND,
> > +     .debug_objects          = 1,
> >       .name                   = "rcu"
> >  };
> >
> > @@ -747,6 +749,7 @@ static struct rcu_torture_ops srcu_ops = {
> >       .cbflood_max    = 50000,
> >       .irq_capable    = 1,
> >       .no_pi_lock     = IS_ENABLED(CONFIG_TINY_SRCU),
> > +     .debug_objects  = 1,
> >       .name           = "srcu"
> >  };
> >
> > @@ -786,6 +789,7 @@ static struct rcu_torture_ops srcud_ops = {
> >       .cbflood_max    = 50000,
> >       .irq_capable    = 1,
> >       .no_pi_lock     = IS_ENABLED(CONFIG_TINY_SRCU),
> > +     .debug_objects  = 1,
> >       .name           = "srcud"
> >  };
> >
> > @@ -3455,7 +3459,6 @@ rcu_torture_cleanup(void)
> >               cur_ops->gp_slow_unregister(NULL);
> >  }
> >
> > -#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
> >  static void rcu_torture_leak_cb(struct rcu_head *rhp)
> >  {
> >  }
> > @@ -3473,7 +3476,6 @@ static void rcu_torture_err_cb(struct rcu_head *rhp)
> >        */
> >       pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
> >  }
> > -#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
> >
> >  /*
> >   * Verify that double-free causes debug-objects to complain, but only
> > @@ -3482,39 +3484,43 @@ static void rcu_torture_err_cb(struct rcu_head *rhp)
> >   */
> >  static void rcu_test_debug_objects(void)
> >  {
> > -#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
> >       struct rcu_head rh1;
> >       struct rcu_head rh2;
> > +     int idx;
> > +
> > +     if (!IS_ENABLED(CONFIG_DEBUG_OBJECTS_RCU_HEAD)) {
> > +             pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_%s()\n",
> > +                                     KBUILD_MODNAME, cur_ops->name);
> > +             return;
> > +     }
> > +
> > +     if (WARN_ON_ONCE(cur_ops->debug_objects &&
> > +                     (!cur_ops->call || !cur_ops->cb_barrier)))
> > +             return;
> > +
> >       struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
> >
> >       init_rcu_head_on_stack(&rh1);
> >       init_rcu_head_on_stack(&rh2);
> > -     pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
> > +     pr_alert("%s: WARN: Duplicate call_%s() test starting.\n", KBUILD_MODNAME, cur_ops->name);
> >
> >       /* Try to queue the rh2 pair of callbacks for the same grace period. */
> > -     preempt_disable(); /* Prevent preemption from interrupting test. */
> > -     rcu_read_lock(); /* Make it impossible to finish a grace period. */
> > -     call_rcu_hurry(&rh1, rcu_torture_leak_cb); /* Start grace period. */
> > -     local_irq_disable(); /* Make it harder to start a new grace period. */
> > -     call_rcu_hurry(&rh2, rcu_torture_leak_cb);
> > -     call_rcu_hurry(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
> > +     idx = cur_ops->readlock(); /* Make it impossible to finish a grace period. */
> > +     cur_ops->call(&rh1, rcu_torture_leak_cb); /* Start grace period. */
> > +     cur_ops->call(&rh2, rcu_torture_leak_cb);
> > +     cur_ops->call(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
> >       if (rhp) {
> > -             call_rcu_hurry(rhp, rcu_torture_leak_cb);
> > -             call_rcu_hurry(rhp, rcu_torture_err_cb); /* Another duplicate callback. */
> > +             cur_ops->call(rhp, rcu_torture_leak_cb);
> > +             cur_ops->call(rhp, rcu_torture_err_cb); /* Another duplicate callback. */
> >       }
> > -     local_irq_enable();
> > -     rcu_read_unlock();
> > -     preempt_enable();
> > +     cur_ops->readunlock(idx);
> >
> >       /* Wait for them all to get done so we can safely return. */
> > -     rcu_barrier();
> > -     pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
> > +     cur_ops->cb_barrier();
> > +     pr_alert("%s: WARN: Duplicate call_%s() test complete.\n", KBUILD_MODNAME, cur_ops->name);
>
> This will get us "call_srcud() test", but if there are complaints yet
> another string can be added to the nrcu_torture_ops structure.
>
> So I have queued this for testing and further review.

Thanks, Paul, I think I should add my test results, the attachment
is the test results :) .

Thanks
Zqiang

>
>                                                         Thanx, Paul
>
> >       destroy_rcu_head_on_stack(&rh1);
> >       destroy_rcu_head_on_stack(&rh2);
> >       kfree(rhp);
> > -#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
> > -     pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
> > -#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
> >  }
> >
> >  static void rcutorture_sync(void)
> > --
> > 2.17.1
> >