From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: John Ogness <john.ogness@linutronix.de>
Cc: Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
linux-kernel@vger.kernel.org,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: Re: [PATCH v3] printk: use atomic updates for klogd work
Date: Mon, 14 Feb 2022 14:35:41 +0900 [thread overview]
Message-ID: <YgnqLe9pWsbhV4kF@google.com> (raw)
In-Reply-To: <87iltld4ue.fsf@jogness.linutronix.de>
On (22/02/11 12:29), John Ogness wrote:
> The per-cpu @printk_pending variable can be updated from
> sleepable contexts, such as:
>
> get_random_bytes()
> warn_unseeded_randomness()
> printk_deferred()
> defer_console_output()
>
> and can be updated from interrupt contexts, such as:
>
> handle_irq_event_percpu()
> __irq_wake_thread()
> wake_up_process()
> try_to_wake_up()
> select_task_rq()
> select_fallback_rq()
> printk_deferred()
> defer_console_output()
>
> and can be updated from NMI contexts, such as:
>
> vprintk()
> if (in_nmi()) defer_console_output()
>
> Therefore the atomic variant of the updating functions must be used.
>
> Replace __this_cpu_xchg() with this_cpu_xchg().
> Replace __this_cpu_or() with this_cpu_or().
>
> Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Signed-off-by: John Ogness <john.ogness@linutronix.de>
FWIW
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
next prev parent reply other threads:[~2022-02-14 5:35 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-03 11:29 [PATCH] printk: defer_console_output: do not assume interrupts disabled John Ogness
2022-02-03 11:33 ` Sebastian Andrzej Siewior
2022-02-04 7:04 ` Sergey Senozhatsky
2022-02-07 9:46 ` [PATCH v2] printk: defer_console_output: use atomic update John Ogness
2022-02-10 15:47 ` Petr Mladek
2022-02-11 11:22 ` John Ogness
2022-02-11 11:23 ` [PATCH v3] printk: use atomic updates for klogd work John Ogness
2022-02-14 5:35 ` Sergey Senozhatsky [this message]
2022-02-15 15:26 ` Petr Mladek
2022-02-14 5:32 ` [PATCH v2] printk: defer_console_output: use atomic update Sergey Senozhatsky
2022-02-14 5:35 ` Sergey Senozhatsky
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