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References: <20220917015852.3833820-1-floridsleeves@gmail.com> <YycYDn82QQZYfpsl@google.com>
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From:   Li Zhong <floridsleeves@gmail.com>
Date:   Mon, 19 Sep 2022 15:28:11 -0700
Message-ID: <CAMEuxRqpQeQoNsbzFf8ZZ6=SfiZ0LA64yfZ7yv3xjfUGK7vyyw@mail.gmail.com>
Subject: Re: [PATCH v1] kernel/printk: check return value of console_trylock()
To:     Sergey Senozhatsky <senozhatsky@chromium.org>
Cc:     linux-kernel@vger.kernel.org, tony.luck@intel.com,
        ccross@android.com, anton@enomsg.org, keescook@chromium.org,
        john.ogness@linutronix.de, rostedt@goodmis.org, pmladek@suse.com
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On Sun, Sep 18, 2022 at 6:11 AM Sergey Senozhatsky
<senozhatsky@chromium.org> wrote:
>
> On (22/09/16 18:58), Li Zhong wrote:
> > Check the console_trylock() return value in case it fails.
> [..]
> > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> > index a1a81fd9889b..2c6a0484315b 100644
> > --- a/kernel/printk/printk.c
> > +++ b/kernel/printk/printk.c
> > @@ -2937,7 +2937,8 @@ void console_flush_on_panic(enum con_flush_mode mode)
> >        * context and we don't want to get preempted while flushing,
> >        * ensure may_schedule is cleared.
> >        */
> > -     console_trylock();
> > +     if (!console_trylock())
> > +             return;
>
> It supposed to be ignored and the comment above (in the code)
> explains why: this is panic flush, we want to proceed regardless.

Thanks for your explanation.