From: Frederic Weisbecker <frederic@kernel.org>
To: Zqiang <qiang.zhang1211@gmail.com>
Cc: paulmck@kernel.org, neeraj.upadhyay@kernel.org,
joel@joelfernandes.org, urezki@gmail.com, boqun.feng@gmail.com,
rcu@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access
Date: Tue, 8 Jul 2025 15:54:22 +0200 [thread overview]
Message-ID: <aG0jDkBqPGm9-Wia@localhost.localdomain> (raw)
In-Reply-To: <20250507112605.20910-3-qiang.zhang1211@gmail.com>
Le Wed, May 07, 2025 at 07:26:05PM +0800, Zqiang a écrit :
> In the preparation stage of CPU online, if the corresponding
> the rdp's->nocb_cb_kthread does not exist, will be created,
> there is a situation where the rdp's rcuop kthreads creation fails,
> and then de-offload this CPU's rdp, does not assign this CPU's
> rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and
> rdp's->rdp_gp->nocb_gp_kthread is still valid.
>
> This will cause the subsequent re-offload operation of this offline
> CPU, which will pass the conditional check and the kthread_unpark()
> will access invalid rdp's->nocb_cb_kthread pointer.
>
> This commit therefore use rdp's->nocb_gp_kthread instead of
> rdp_gp's->nocb_gp_kthread for safety check.
>
> Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
--
Frederic Weisbecker
SUSE Labs
next prev parent reply other threads:[~2025-07-08 13:54 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-07 11:26 [PATCH] rcutorture: Fix rcutorture_one_extend_check() splat in RT kernels Zqiang
2025-05-07 11:26 ` [PATCH v2] rcu/nocb: Add Safe checks for access offloaded rdp Zqiang
2025-05-07 16:06 ` Joel Fernandes
2025-05-07 16:31 ` Frederic Weisbecker
2025-05-07 16:52 ` Joel Fernandes
2025-05-07 16:25 ` Frederic Weisbecker
2025-05-08 6:43 ` Z qiang
2025-05-08 13:03 ` Z qiang
2025-05-09 13:33 ` Frederic Weisbecker
2025-05-09 18:56 ` Joel Fernandes
2025-05-07 11:26 ` [PATCH] rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access Zqiang
2025-05-08 21:14 ` Paul E. McKenney
2025-05-09 3:32 ` Z qiang
2025-05-09 3:45 ` Paul E. McKenney
2025-05-09 19:07 ` Joel Fernandes
2025-05-09 19:11 ` Joel Fernandes
2025-05-16 8:15 ` Z qiang
2025-07-08 13:54 ` Frederic Weisbecker [this message]
2025-05-07 21:04 ` [PATCH] rcutorture: Fix rcutorture_one_extend_check() splat in RT kernels Paul E. McKenney
2025-05-09 19:14 ` Joel Fernandes
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