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From: John Ogness <john.ogness@linutronix.de>
To: debarbos@redhat.com, williams@redhat.com
Cc: linux-rt-users@vger.kernel.org
Subject: Re: [PATCH] v6.6-rt-stable: printk/nbcon: Fix Illegal RCU Usage
Date: Mon, 21 Oct 2024 23:02:18 +0206	[thread overview]
Message-ID: <84msix5g5p.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <ZxZ5WXV6umbL9XG9@debarbos-thinkpadt14sgen2i.remote.csb>

On 2024-10-21, Derek Barbosa <debarbos@redhat.com> wrote:
> From 1188b21c357dcb750a6851d7e5fd2d1f70ca9690 Mon Sep 17 00:00:00 2001
> From: Derek Barbosa <debarbos@redhat.com>
> Date: Mon, 21 Oct 2024 11:30:30 -0400
> Subject: [PATCH 1/1] [PATCH] printk: nbcon: Fix illegal RCU usage on thread
>  wakeup
>
> In debug kernels, printk'ing during the SMP startup of a secondary CPU
> results in a splat [0] on boot that details illegal RCU usage from
> offline CPUs.
>
> This patch aligns rcuwait_has_sleeper() with what currently exists in
> Torvalds' tree, at commit 76f258bf3f2aa, and will avoid the
> aforementioned splat.
>
> Furthermore, this patch makes it so that we avoid the use of hacky
> rcu_derefrencing through the waiter's task struct,and instead leverages
> the correct RCU API with the rcuwait_active() function.
>
> [0] https://lore.kernel.org/linux-rt-users/5x4nejpojrtny37k7l6loewqwuaituq77zc3tkkojvawcuvmml@thwg65fdb3vn/
>
> Signed-off-by: Derek Barbosa <debarbos@redhat.com>

Thanks!

Reviewed-by: John Ogness <john.ogness@linutronix.de>

  reply	other threads:[~2024-10-21 20:56 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-21 15:55 [PATCH] v6.6-rt-stable: printk/nbcon: Fix Illegal RCU Usage Derek Barbosa
2024-10-21 20:56 ` John Ogness [this message]
2024-10-21 22:28   ` Clark Williams
2024-11-04 11:44 ` Sebastian Andrzej Siewior

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