From: Petr Mladek <pmladek@suse.com>
To: Chris Down <chris@chrisdown.name>
Cc: linux-kernel@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
John Ogness <john.ogness@linutronix.de>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Tony Lindgren <tony.lindgren@linux.intel.com>,
kernel-team@fb.com
Subject: Re: [PATCH v8 06/21] printk: nbcon: Synchronise console unregistration against atomic flushers
Date: Wed, 10 Dec 2025 16:12:53 +0100 [thread overview]
Message-ID: <aTmN9fUiJt5gm6Vq@pathway> (raw)
In-Reply-To: <e763af8ab34d96fcd02e76ad7b41f6b95c78850a.1764272407.git.chris@chrisdown.name>
On Fri 2025-11-28 03:43:32, Chris Down wrote:
> The nbcon atomic flush path in __nbcon_atomic_flush_pending_con() calls
> nbcon_emit_next_record(), which uses console_srcu_read_flags() to read
> the console flags. console_srcu_read_flags() expects to be called under
> console_srcu_read_lock(), but the atomic flush path does not hold this
> lock.
__nbcon_atomic_flush_pending_con() seems to be called in the following
code paths:
+ __nbcon_atomic_flush_pending()
+ nbcon_atomic_flush_pending_con()
+ __nbcon_atomic_flush_pending_con()
+ nbcon_device_release()
+ __nbcon_atomic_flush_pending_con()
+ kdb_msg_write() # new in 6.19-rc1
+ nbcon_kdb_release()
+ __nbcon_atomic_flush_pending_con()
And all three callers take console_srcu_read_lock() because
they need it for other reasons. So, we should be on the safe
side and do not need this change.
Or do I miss some code path, please?
Best Regards,
Petr
next prev parent reply other threads:[~2025-12-10 15:12 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-27 19:43 [PATCH v8 00/21] printk: console: Per-console loglevels Chris Down
2025-11-27 19:43 ` [PATCH v8 01/21] printk: Fully resolve loglevel before deciding printk delay suppression Chris Down
2025-12-09 16:40 ` Petr Mladek
2025-12-11 14:49 ` Petr Mladek
2025-12-11 15:28 ` Petr Mladek
2025-11-27 19:43 ` [PATCH v8 02/21] printk: Avoid spuriously delaying messages not solicited by any console Chris Down
2025-11-27 19:43 ` [PATCH v8 03/21] printk: Prioritise user-specified configuration over SPCR/DT Chris Down
2025-12-10 14:38 ` Petr Mladek
2025-11-27 19:43 ` [PATCH v8 04/21] printk: Use effective loglevel for suppression and extended console state Chris Down
2025-11-27 19:43 ` [PATCH v8 05/21] printk: console: Add per-console loglevel support to struct console Chris Down
2025-11-27 19:43 ` [PATCH v8 06/21] printk: nbcon: Synchronise console unregistration against atomic flushers Chris Down
2025-12-10 15:12 ` Petr Mladek [this message]
2025-11-27 19:43 ` [PATCH v8 07/21] printk: Introduce per-console loglevel support Chris Down
2025-11-27 19:43 ` [PATCH v8 08/21] printk: Iterate registered consoles for delay suppression decisions Chris Down
2025-11-27 19:43 ` [PATCH v8 09/21] printk: Optimise printk_delay() to avoid walking consoles under SRCU Chris Down
2025-12-11 14:37 ` Petr Mladek
2025-11-27 19:43 ` [PATCH v8 10/21] printk: Add synchronisation for concurrent console state changes Chris Down
2025-11-27 19:43 ` [PATCH v8 11/21] printk: Add ignore_per_console_loglevel module parameter Chris Down
2025-11-27 19:43 ` [PATCH v8 12/21] printk: Ensure sysrq output bypasses per-console filtering Chris Down
2025-11-27 19:44 ` [PATCH v8 13/21] printk: Toggle ignore_per_console_loglevel via syslog Chris Down
2025-11-27 19:44 ` [PATCH v8 14/21] printk: console: Introduce sysfs interface for per-console loglevels Chris Down
2025-12-12 14:04 ` Petr Mladek
2025-11-27 19:44 ` [PATCH v8 15/21] printk: sysrq: Clamp console loglevel to valid range Chris Down
2025-12-12 14:10 ` Petr Mladek
2025-11-27 19:44 ` [PATCH v8 16/21] printk: Constrain hardware-addressed console checks to name position Chris Down
2025-11-27 19:44 ` [PATCH v8 17/21] printk: Support setting initial console loglevel via console= on cmdline Chris Down
2025-11-27 19:44 ` [PATCH v8 18/21] printk: Deconstruct kernel.printk into discrete sysctl controls Chris Down
2025-12-12 15:24 ` Petr Mladek
2025-12-15 10:08 ` Joel Granados
2025-12-15 16:09 ` Petr Mladek
2025-11-27 19:44 ` [PATCH v8 19/21] printk: docs: Add comprehensive guidance for per-console loglevels Chris Down
2025-12-12 15:32 ` Petr Mladek
2025-11-27 19:44 ` [PATCH v8 20/21] printk: Deprecate the kernel.printk sysctl interface Chris Down
2025-12-12 15:51 ` Petr Mladek
2025-12-15 9:52 ` Joel Granados
2025-12-15 16:06 ` Petr Mladek
2025-12-17 11:47 ` Joel Granados
2025-12-17 14:33 ` Geert Uytterhoeven
2025-12-17 16:04 ` Steven Rostedt
2025-12-17 20:23 ` Joel Granados
2025-11-27 19:44 ` [PATCH v8 21/21] printk: Purge default_console_loglevel Chris Down
2025-12-12 16:11 ` [PATCH v8 00/21] printk: console: Per-console loglevels Petr Mladek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=aTmN9fUiJt5gm6Vq@pathway \
--to=pmladek@suse.com \
--cc=chris@chrisdown.name \
--cc=geert@linux-m68k.org \
--cc=gregkh@linuxfoundation.org \
--cc=john.ogness@linutronix.de \
--cc=kernel-team@fb.com \
--cc=linux-kernel@vger.kernel.org \
--cc=rostedt@goodmis.org \
--cc=senozhatsky@chromium.org \
--cc=tony.lindgren@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.