From: Petr Mladek <pmladek@suse.com>
To: John Ogness <john.ogness@linutronix.de>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH printk v2 05/12] printk: add macro for console detail messages
Date: Wed, 6 Apr 2022 12:31:59 +0200 [thread overview]
Message-ID: <Yk1sH5huJa6dayqJ@alley> (raw)
In-Reply-To: <20220405132535.649171-6-john.ogness@linutronix.de>
On Tue 2022-04-05 15:31:28, John Ogness wrote:
> It is useful to generate log messages that include details about
> the related console. Rather than duplicate the logic to assemble
> the details, put that logic into a macro printk_console_msg().
>
> Once console printers become threaded, this macro will find many
> users.
I really like this idea.
> Signed-off-by: John Ogness <john.ogness@linutronix.de>
> ---
> kernel/printk/printk.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index fb9a6eaf54fd..39ca9d758e52 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -2993,6 +2993,10 @@ static void try_enable_default_console(struct console *newcon)
> newcon->flags |= CON_CONSDEV;
> }
>
> +#define printk_console_msg(c, lvl, msg) \
> + printk(lvl pr_fmt("%sconsole [%s%d] " msg "\n"), \
> + (c->flags & CON_BOOT) ? "boot" : "", c->name, c->index)
This might be dangerous because "msg" is handled as printk format.
Any potential %<modifier> might cause unexpected memory access.
Honestly, I am not good at writing macros. I played with it and
the following worked for me:
#define printk_console_msg(c, lvl, fmt, ...) \
printk(lvl pr_fmt("%sconsole [%s%d] " fmt), \
(c->flags & CON_BOOT) ? "boot" : "", \
c->name, c->index, \
##__VA_ARGS__)
Note that it requires adding "\n" back to the callers.
Also, please, call it "console_printk()" or so. It needs extra
arguments and this name will help to distinguish it from
the plain printk() wrappers. From my POV, it is something like,
for example, dev_printk(), snd_printk(), or xfs_printk_ratelimited().
Best Regards,
Petr
next prev parent reply other threads:[~2022-04-06 13:36 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-05 13:25 [PATCH printk v2 00/12] implement threaded console printing John Ogness
2022-04-05 13:25 ` [PATCH printk v2 01/12] printk: rename cpulock functions John Ogness
2022-04-06 9:07 ` Petr Mladek
2022-04-05 13:25 ` [PATCH printk v2 02/12] printk: cpu sync always disable interrupts John Ogness
2022-04-05 13:25 ` [PATCH printk v2 03/12] printk: get caller_id/timestamp after migration disable John Ogness
2022-04-05 13:25 ` [PATCH printk v2 04/12] printk: call boot_delay_msec() in printk_delay() John Ogness
2022-04-05 13:25 ` [PATCH printk v2 05/12] printk: add macro for console detail messages John Ogness
2022-04-06 10:31 ` Petr Mladek [this message]
2022-04-05 13:25 ` [PATCH printk v2 06/12] printk: refactor and rework printing logic John Ogness
2022-04-06 14:02 ` Petr Mladek
2022-04-05 13:25 ` [PATCH printk v2 07/12] printk: move buffer definitions into console_emit_next_record() caller John Ogness
2022-04-06 14:40 ` Petr Mladek
2022-04-05 13:25 ` [PATCH printk v2 08/12] printk: add pr_flush() John Ogness
2022-04-06 15:17 ` Petr Mladek
2022-04-08 18:57 ` John Ogness
2022-04-05 13:25 ` [PATCH printk v2 09/12] printk: add functions to prefer direct printing John Ogness
2022-04-07 9:56 ` Petr Mladek
2022-04-07 13:35 ` Helge Deller
2022-04-07 14:35 ` John Ogness
2022-04-07 19:36 ` Helge Deller
2022-04-07 20:04 ` John Ogness
2022-04-07 20:20 ` Helge Deller
2022-04-11 12:50 ` Petr Mladek
2022-04-09 15:57 ` Paul E. McKenney
2022-04-05 13:25 ` [PATCH printk v2 10/12] printk: add kthread console printers John Ogness
2022-04-07 16:43 ` start/stop: was: " Petr Mladek
2022-04-07 16:49 ` console_is_usable() check: " Petr Mladek
2022-04-07 16:53 ` wake_up_klogd(): " Petr Mladek
2022-04-07 16:56 ` console_flush_all(): was: : was " Petr Mladek
2022-04-05 13:25 ` [PATCH printk v2 11/12] printk: extend console_lock for proper kthread support John Ogness
2022-04-08 13:45 ` guarantee forward progress: was: " Petr Mladek
2022-04-08 20:17 ` John Ogness
2022-04-11 10:45 ` Petr Mladek
2022-04-08 13:52 ` register_console: " Petr Mladek
2022-04-05 13:25 ` [PATCH printk v2 12/12] printk: remove @console_locked John Ogness
2022-04-05 15:03 ` [PATCH printk v2 00/12] implement threaded console printing Andy Shevchenko
2022-04-05 21:24 ` John Ogness
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