From: Frederic Weisbecker <frederic@kernel.org>
To: Joel Fernandes <joel@joelfernandes.org>
Cc: Joel Fernandes <joelagnelf@nvidia.com>,
Paul E McKenney <paulmck@kernel.org>,
Boqun Feng <boqun.feng@gmail.com>,
rcu@vger.kernel.org, Neeraj Upadhyay <neeraj.upadhyay@kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
Uladzislau Rezki <urezki@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Zqiang <qiang.zhang@linux.dev>, Shuah Khan <shuah@kernel.org>,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
Kai Yao <yaokai34@huawei.com>, Tengda Wu <wutengda2@huawei.com>
Subject: Re: [PATCH -next 1/8] rcu: Fix rcu_read_unlock() deadloop due to softirq
Date: Thu, 8 Jan 2026 16:39:19 +0100 [thread overview]
Message-ID: <aV_Pp5BUxB9dwp1S@localhost.localdomain> (raw)
In-Reply-To: <9086EA4F-0393-4E01-AE74-1B428904BFCE@joelfernandes.org>
Le Wed, Jan 07, 2026 at 10:35:44PM -0500, Joel Fernandes a écrit :
> >
> > By the way, when I last tried to do it from rcu_qs, it was not fixing the original bug with the IRQ work recursion.
> >
> > I found that it was always resetting the flag. But probably it is not even the right place to do it in the first place.
>
> I think we need to reset the flag in rcu_report_exp_rdp() as well if exp_hint
> is set and we reported exp qs.
To avoid needlessly reaching the rcu_read_unlock() slowpath whenever the exp QS has
already been reported, yes indeed.
> I am working on a series to cover all cases and will send RFC soon. However this patch we are
> reviewing can go in for this merge window and the rest I am preparing (for
> further improvement) for the next merge window, if that sounds good.
Ok.
--
Frederic Weisbecker
SUSE Labs
next prev parent reply other threads:[~2026-01-08 15:39 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-01 16:34 [PATCH -next 0/8] RCU updates from me for next merge window Joel Fernandes
2026-01-01 16:34 ` [PATCH -next 1/8] rcu: Fix rcu_read_unlock() deadloop due to softirq Joel Fernandes
2026-01-02 17:28 ` Steven Rostedt
2026-01-02 17:30 ` Steven Rostedt
2026-01-02 19:51 ` Paul E. McKenney
2026-01-03 0:41 ` Joel Fernandes
2026-01-04 3:20 ` Yao Kai
2026-01-05 17:16 ` Steven Rostedt
2026-01-09 16:38 ` Steven Rostedt
2026-01-04 10:00 ` Boqun Feng
2026-01-07 23:14 ` Frederic Weisbecker
2026-01-08 1:02 ` Joel Fernandes
2026-01-08 1:35 ` Joel Fernandes
2026-01-08 3:35 ` Joel Fernandes
2026-01-08 15:39 ` Frederic Weisbecker [this message]
2026-01-08 15:57 ` Mathieu Desnoyers
2026-01-08 15:25 ` Frederic Weisbecker
2026-01-09 1:12 ` Joel Fernandes
2026-01-09 14:23 ` Frederic Weisbecker
2026-01-01 16:34 ` [PATCH -next 2/8] srcu: Use suitable gfp_flags for the init_srcu_struct_nodes() Joel Fernandes
2026-01-01 16:34 ` [PATCH -next 3/8] rcu/nocb: Remove unnecessary WakeOvfIsDeferred wake path Joel Fernandes
2026-01-08 15:57 ` Frederic Weisbecker
2026-01-09 1:39 ` Joel Fernandes
2026-01-09 10:32 ` Boqun Feng
2026-01-09 11:20 ` Joel Fernandes
2026-01-11 12:14 ` Boqun Feng
2026-01-01 16:34 ` [PATCH -next 4/8] rcu/nocb: Add warning if no rcuog wake up attempt happened during overload Joel Fernandes
2026-01-08 17:22 ` Frederic Weisbecker
2026-01-09 3:49 ` Joel Fernandes
2026-01-09 14:36 ` Frederic Weisbecker
2026-01-09 21:20 ` Joel Fernandes
2026-01-01 16:34 ` [PATCH -next 5/8] rcu/nocb: Add warning to detect if overload advancement is ever useful Joel Fernandes
2026-01-14 1:09 ` Joel Fernandes
2026-01-01 16:34 ` [PATCH -next 6/8] rcu: Reduce synchronize_rcu() latency by reporting GP kthread's CPU QS early Joel Fernandes
2026-01-01 16:34 ` [PATCH -next 7/8] rcutorture: Prevent concurrent kvm.sh runs on same source tree Joel Fernandes
2026-01-01 16:34 ` [PATCH -next 8/8] rcutorture: Add --kill-previous option to terminate previous kvm.sh runs Joel Fernandes
2026-01-01 22:48 ` Paul E. McKenney
2026-01-04 10:55 ` [PATCH -next 0/8] RCU updates from me for next merge window Boqun Feng
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