Date:   Wed, 22 Feb 2023 15:42:37 -0300
From:   Wander Lairson Costa <wander@redhat.com>
To:     luca abeni <luca.abeni@santannapisa.it>
Cc:     Daniel Bristot de Oliveira <bristot@redhat.com>,
        Valentin Schneider <vschneid@redhat.com>,
        Oleg Nesterov <oleg@redhat.com>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Stafford Horne <shorne@gmail.com>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Andy Lutomirski <luto@kernel.org>,
        "Liam R. Howlett" <Liam.Howlett@oracle.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Andrei Vagin <avagin@gmail.com>,
        open list <linux-kernel@vger.kernel.org>,
        Paul McKenney <paulmck@kernel.org>
Subject: Re: [PATCH v2 1/4] sched/task: Add the put_task_struct_atomic_safe
 function
Message-ID: <20230222184237.hkfznxm3ts3gye2i@fedora>
References: <20230120150246.20797-1-wander@redhat.com>
 <20230120150246.20797-2-wander@redhat.com>
 <20230123163002.GB6268@redhat.com>
 <CAAq0SUk1vfNDuzGbXNftgW4wq4PC_EzMhpq4E=RBQNkOB3f4YQ@mail.gmail.com>
 <xhsmhbkmkdla4.mognet@vschneid.remote.csb>
 <CAAq0SUnUH6DEjwEs2RxRCtkTU121JXpdsV_rZky1d0Bo04=fiQ@mail.gmail.com>
 <8632d9c6-7ec7-c3aa-f9e7-fa63cc82f6ae@redhat.com>
 <20230217200437.551ad7c2@nowhere>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230217200437.551ad7c2@nowhere>
Precedence: bulk

On Fri, Feb 17, 2023 at 08:04:37PM +0100, luca abeni wrote:
> Hi all,
> 
> On Fri, 17 Feb 2023 14:35:22 -0300
> Daniel Bristot de Oliveira <bristot@redhat.com> wrote:
> 
> > On 1/30/23 08:49, Wander Lairson Costa wrote:
> > >> Another thing, if you look at release_task_stack(), it either
> > >> caches the outgoing stack for later use, or frees it via RCU
> > >> (regardless of PREEMPT_RT). Perhaps we could follow that and just
> > >> always punt the freeing of the task struct to RCU?
> > >>  
> > > That's a point. Do you mean doing that even for !PREEMPT_RT?
> > >   
> > 
> > It seems that Luca Abeni (in Cc) is hitting the bug in the non-rt
> > kernel with SCHED_DEADLINE...
> > 
> > adding him to the thread.
> 
> Thanks Daniel for adding me.
> 
> I triggered this "BUG: Invalid wait context" with a 5.15.76 kernel,
> without PREEMPT_RT. I can reproduce it easily on a KVM-based VM; if
> more information or tests are needed, let me know.
> 

Does it happen in linux-6.1 or linux-6.2?

> 
> 			Luca
>