From: John Ogness <john.ogness@linutronix.de>
To: Petr Mladek <pmladek@suse.com>
Cc: Chris Down <chris@chrisdown.name>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Tony Lindgren <tony.lindgren@linux.intel.com>,
kernel-team@fb.com
Subject: Re: [PATCH v6 06/11] printk: console: Introduce sysfs interface for per-console loglevels
Date: Wed, 20 Nov 2024 16:35:32 +0106 [thread overview]
Message-ID: <84ed35rkir.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <Zz34GgmFbuZKQOzG@pathway.suse.cz>
On 2024-11-20, Petr Mladek <pmladek@suse.com> wrote:
>> +static ssize_t loglevel_show(struct device *dev, struct device_attribute *attr,
>> + char *buf)
>> +{
>> + struct console *con = dev_get_drvdata(dev);
>> +
>> + return sysfs_emit(buf, "%d\n", READ_ONCE(con->level));
>
> Honestly, it seems that everyone agrees that the READ_ONCE() makes
> some sense. I do not understand why some many people wants to remove
> it. I personally prefer to be on the safe side.
OK, then please also annotate the data race to keep KCSAN happy:
data_race(READ_ONCE(con->level));
From the data_race kerneldoc:
If the access must be atomic *and* KCSAN should ignore the access,
use both data_race() and READ_ONCE(), for example,
data_race(READ_ONCE(x)).
John
next prev parent reply other threads:[~2024-11-20 15:29 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-28 16:45 [PATCH v6 00/11] printk: console: Per-console loglevels Chris Down
2024-10-28 16:45 ` [PATCH v6 01/11] printk: Avoid delaying messages that aren't solicited by any console Chris Down
2024-10-28 16:45 ` [PATCH v6 02/11] printk: Use struct console for suppression and extended console state Chris Down
2024-11-08 9:57 ` Petr Mladek
2024-11-15 8:30 ` John Ogness
2024-11-20 4:17 ` Chris Down
2024-11-20 12:03 ` Petr Mladek
2024-10-28 16:45 ` [PATCH v6 03/11] printk: console: Implement core per-console loglevel infrastructure Chris Down
2024-11-08 16:10 ` Petr Mladek
2024-11-12 10:25 ` Petr Mladek
2024-11-14 16:51 ` Petr Mladek
2024-10-28 16:45 ` [PATCH v6 04/11] printk: Support toggling per-console loglevel via syslog() and cmdline Chris Down
2024-11-12 10:56 ` Conflict with FORCE_CON: " Petr Mladek
2024-11-14 19:28 ` Chris Down
2024-11-15 11:41 ` Petr Mladek
2024-11-12 12:59 ` Petr Mladek
2024-11-14 17:14 ` syslog warning: was: " Petr Mladek
2024-11-14 18:53 ` Chris Down
2024-11-15 11:36 ` Petr Mladek
2024-10-28 16:45 ` [PATCH v6 05/11] MAINTAINERS: Mark printk-basics.rst as owned by printk subsystem Chris Down
2024-10-28 23:26 ` Thomas Gleixner
2024-10-28 23:52 ` Chris Down
2024-11-12 13:00 ` Petr Mladek
2024-10-28 16:45 ` [PATCH v6 06/11] printk: console: Introduce sysfs interface for per-console loglevels Chris Down
2024-11-13 15:58 ` Petr Mladek
2024-11-13 15:59 ` register_device: was: " Petr Mladek
2024-11-14 18:41 ` Chris Down
2024-11-15 4:08 ` Greg Kroah-Hartman
2024-11-18 15:19 ` Petr Mladek
2024-11-15 4:20 ` Greg Kroah-Hartman
2024-11-15 14:09 ` Petr Mladek
2024-11-20 5:01 ` Chris Down
2024-11-20 8:43 ` John Ogness
2024-11-20 14:54 ` Petr Mladek
2024-11-20 15:29 ` John Ogness [this message]
2024-11-20 14:45 ` Petr Mladek
2025-01-10 10:27 ` Joel Granados
2025-01-15 10:31 ` Petr Mladek
2024-10-28 16:45 ` [PATCH v6 07/11] printk: Constrain hardware-addressed console checks to name position Chris Down
2024-10-29 8:26 ` Tony Lindgren
2024-11-13 16:11 ` Petr Mladek
2024-10-28 16:45 ` [PATCH v6 08/11] printk: Support setting initial console loglevel via console= on cmdline Chris Down
2024-11-14 9:11 ` Petr Mladek
2024-10-28 16:45 ` [PATCH v6 09/11] printk: Add sysctl interface to set global loglevels Chris Down
2024-11-14 16:21 ` Petr Mladek
2025-01-10 10:09 ` Joel Granados
2024-10-28 16:45 ` [PATCH v6 10/11] printk: Deprecate the kernel.printk sysctl interface Chris Down
2024-11-14 16:25 ` Petr Mladek
2024-10-28 16:46 ` [PATCH v6 11/11] printk: Purge default_console_loglevel Chris Down
2024-11-14 16:38 ` Petr Mladek
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