From: Mike Galbraith <efault@gmx.de>
To: John Ogness <john.ogness@linutronix.de>,
Breno Leitao <leitao@debian.org>,
Simon Horman <horms@kernel.org>,
kuba@kernel.org, calvin@wbinvd.org
Cc: Pavel Begunkov <asml.silence@gmail.com>,
Johannes Berg <johannes@sipsolutions.net>,
paulmck@kernel.org, LKML <linux-kernel@vger.kernel.org>,
netdev@vger.kernel.org, boqun.feng@gmail.com
Subject: Re: netconsole: HARDIRQ-safe -> HARDIRQ-unsafe lock order warning
Date: Mon, 08 Sep 2025 17:18:02 +0200 [thread overview]
Message-ID: <ce0c55a168166ae772b6247cf16fb21f990e3482.camel@gmx.de> (raw)
In-Reply-To: <84frcx842e.fsf@jogness.linutronix.de>
On Mon, 2025-09-08 at 15:36 +0206, John Ogness wrote:
>
> Just be aware that ->write_atomic() will be called from _any_ context
> (including scheduler and NMI) and a console implementing this callback
> must handle the message or the message is lost for that console.
What I did locally was to steal panic_in_progress() from printk.c and
use that as the barrier between immediate xmit and queue for kworker
should locking challenged parties notice IRQs are off despite selective
bending up of NETPOLL's definition of "poll".
Not perfect, but safety first seems prudent, and not bad given the
panic_on knobs available.
-Mike
next prev parent reply other threads:[~2025-09-08 15:18 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-13 4:14 Mike Galbraith
2025-08-14 10:16 ` Breno Leitao
2025-08-14 15:45 ` Pavel Begunkov
2025-08-15 0:23 ` Jakub Kicinski
2025-08-15 10:44 ` Pavel Begunkov
2025-08-15 16:42 ` Jakub Kicinski
2025-08-15 17:29 ` Breno Leitao
2025-08-15 17:33 ` Jakub Kicinski
2025-08-18 12:23 ` Breno Leitao
2025-08-15 19:10 ` Calvin Owens
2025-08-16 9:19 ` Mike Galbraith
2025-08-15 20:02 ` Pavel Begunkov
2025-08-18 12:10 ` Breno Leitao
2025-08-19 17:27 ` Breno Leitao
2025-08-20 12:31 ` Mike Galbraith
2025-08-20 17:36 ` Breno Leitao
2025-08-21 3:37 ` Mike Galbraith
2025-08-21 3:51 ` Mike Galbraith
2025-08-21 17:35 ` Breno Leitao
2025-08-22 3:54 ` Mike Galbraith
2025-08-26 12:43 ` Breno Leitao
2025-08-26 13:56 ` Mike Galbraith
2025-09-05 12:48 ` John Ogness
2025-09-06 2:32 ` Mike Galbraith
2025-09-08 13:30 ` John Ogness
2025-09-08 15:18 ` Mike Galbraith [this message]
2025-09-08 20:27 ` Calvin Owens
2025-09-09 15:49 ` Mike Galbraith
2025-09-10 15:51 ` Petr Mladek
2025-09-09 12:50 ` Breno Leitao
2025-09-10 12:22 ` John Ogness
2025-09-10 15:12 ` Petr Mladek
2025-09-10 18:26 ` Breno Leitao
2025-09-30 13:57 ` Calvin Owens
2025-09-30 14:23 ` John Ogness
2025-09-30 14:30 ` Sebastian Siewior
2025-09-30 17:35 ` Mike Galbraith
2025-10-01 6:00 ` Mike Galbraith
2025-09-11 13:03 ` John Ogness
2025-09-10 18:23 ` Breno Leitao
2025-09-11 13:13 ` John Ogness
2025-08-21 10:06 ` Mike Galbraith
2025-08-21 13:12 ` Mike Galbraith
2025-08-15 17:37 ` Calvin Owens
2025-08-26 14:10 ` Johannes Berg
2025-08-15 12:45 ` Mike Galbraith
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