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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Fri, 20 Nov 2020 09:51:15 +0100
Message-ID: <CACT4Y+bas5xfc-+W+wkpbx6Lw=9dsKv=ha83=hs1pytjfK+drg@mail.gmail.com>
Subject: Re: [PATCH] rcu: kasan: record and print kvfree_call_rcu call stack
To:     "Paul E. McKenney" <paulmck@kernel.org>
Cc:     "Zhang, Qiang" <qiang.zhang@windriver.com>,
        Josh Triplett <josh@joshtriplett.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Joel Fernandes <joel@joelfernandes.org>, rcu@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Uladzislau Rezki <urezki@gmail.com>
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Precedence: bulk

On Thu, Nov 19, 2020 at 10:49 PM Paul E. McKenney <paulmck@kernel.org> wrote:
>
> On Wed, Nov 18, 2020 at 11:53:09AM +0800, qiang.zhang@windriver.com wrote:
> > From: Zqiang <qiang.zhang@windriver.com>
> >
> > Add kasan_record_aux_stack function for kvfree_call_rcu function to
> > record call stacks.
> >
> > Signed-off-by: Zqiang <qiang.zhang@windriver.com>
>
> Thank you, but this does not apply on the "dev" branch of the -rcu tree.
> See file:///home/git/kernel.org/rcutodo.html for more info.
>
> Adding others on CC who might have feedback on the general approach.
>
>                                                         Thanx, Paul
>
> > ---
> >  kernel/rcu/tree.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > index da3414522285..a252b2f0208d 100644
> > --- a/kernel/rcu/tree.c
> > +++ b/kernel/rcu/tree.c
> > @@ -3506,7 +3506,7 @@ void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> >               success = true;
> >               goto unlock_return;
> >       }
> > -
> > +     kasan_record_aux_stack(ptr);
> >       success = kvfree_call_rcu_add_ptr_to_bulk(krcp, ptr);
> >       if (!success) {
> >               run_page_cache_worker(krcp);


kvfree_call_rcu is intended to free objects, right? If so this is:

Acked-by: Dmitry Vyukov <dvyukov@google.com>