linux-kernel - Re: [PATCH 4.19 regression fix] printk: For early boot messages check loglevel when flushing the buffer

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Date:   Wed, 5 Sep 2018 17:33:26 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Cc:     Hans de Goede <hdegoede@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        x86@...nel.org, linux-kernel@...r.kernel.org,
        Steven Rostedt <rostedt@...dmis.org>,
        Petr Mladek <pmladek@...e.com>,
        Maninder Singh <maninder1.s@...sung.com>
Subject: Re: [PATCH 4.19 regression fix] printk: For early boot messages
 check loglevel when flushing the buffer

On (09/05/18 14:36), Sergey Senozhatsky wrote:
> 
> Just a demonstration of the idea. It does not look very good, tho.
> I'd rather have just one suppress_message_printing() in printk code.
> 
> // This is not a proposed patch, hence the 80-cols violation.
> 
> ---
> 
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index c036f128cdc3..231ac18423e1 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -2416,7 +2416,7 @@ void console_unlock(void)
>  			break;
>  
>  		msg = log_from_idx(console_idx);
> -		if (msg->flags & LOG_NOCONS) {
> +		if (msg->flags & LOG_NOCONS || (exclusive_console && suppress_message_printing(msg->level))) {
>  			/*
>  			 * Skip record if !ignore_loglevel, and
>  			 * record has level above the console loglevel.

D'oh... Sorry about that, but, believe it or not, this is completely
not what I had in my mind. What I had, was something like this:

---

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index c036f128cdc3..dadb8c11b0d6 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2416,6 +2416,11 @@ void console_unlock(void)
 			break;
 
 		msg = log_from_idx(console_idx);
+
+		if (exclusive_console &&
+				!suppress_message_printing(msg->level))
+			msg->flags &= ~LOG_NOCONS;
+
 		if (msg->flags & LOG_NOCONS) {
 			/*
 			 * Skip record if !ignore_loglevel, and

---

	-ss