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From: John Ogness <john.ogness@linutronix.de>
To: Mukesh Ojha <quic_mojha@quicinc.com>,
	pmladek@suse.com, rostedt@goodmis.org, senozhatsky@chromium.org
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] printk: Update @console_may_schedule in console_trylock_spinning()
Date: Mon, 26 Feb 2024 14:08:40 +0106	[thread overview]
Message-ID: <8734tfml8v.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <44648e78-d117-2f6a-8ecd-f0a29327fa4f@quicinc.com>

On 2024-02-26, Mukesh Ojha <quic_mojha@quicinc.com> wrote:
> what if console_trylock_spinning() gets the lock which makes 
> console_may_schedule =1 and it is still schedulable ?

I am afraid I do not understand the question.

console_trylock_spinning() is only called from the printk caller
context. In this context, console_may_schedule is always set to 0.

Only if another context acquires the console lock per sleeping wait,
console_lock(), can console_may_schedule be set to 1.

Note that the value of console_may_schedule is only relevant for the
console lock owner when console_unlock() is called. That is why its
value is set when locking the console (or, with this patch, when
transferring console lock ownerhip).

John

  reply	other threads:[~2024-02-26 13:03 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-22  9:05 [PATCH] printk: Add atomic context check inside console_unlock() Mukesh Ojha
2024-02-22 14:53 ` John Ogness
2024-02-26 10:17   ` Mukesh Ojha
2024-02-26 12:01     ` [PATCH] printk: Update @console_may_schedule in console_trylock_spinning() John Ogness
2024-02-26 12:17       ` Mukesh Ojha
2024-02-26 13:02         ` John Ogness [this message]
2024-02-27 16:37           ` Mukesh Ojha
2024-03-15 16:10       ` Petr Mladek

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