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From: John Ogness <john.ogness@linutronix.de>
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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()
In-Reply-To: <44648e78-d117-2f6a-8ecd-f0a29327fa4f@quicinc.com>
References: <20240222090538.23017-1-quic_mojha@quicinc.com>
 <87plwo5z4k.fsf@jogness.linutronix.de>
 <e5474801-53c1-6bbb-8781-e5cee42d6a90@quicinc.com>
 <875xybmo2z.fsf@jogness.linutronix.de>
 <44648e78-d117-2f6a-8ecd-f0a29327fa4f@quicinc.com>
Date: Mon, 26 Feb 2024 14:08:40 +0106
Message-ID: <8734tfml8v.fsf@jogness.linutronix.de>
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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