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Wed, 14 Oct 2026 02:58:47 -0700 (PDT) Date: Wed, 14 Oct 2026 11:58:45 +0200 From: Petr Mladek To: John Ogness Cc: Sergey Senozhatsky , Steven Rostedt , Pavel Tikhomirov , Oleg Nesterov , Christian Brauner , Sebastian Andrzej Siewior , oe-lkp@lists.linux.dev, lkp@intel.com, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] nbcon/reboot: Switch NBCON consoles into the emergency mode in emergency_restart() Message-ID: References: <20261013154141.94016-1-pmladek@suse.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261013154141.94016-1-pmladek@suse.com> On Tue 2026-10-13 17:41:41, Petr Mladek wrote: > When the system is going down a normal way, the NBCON kthreads are > flushed and stopped properly via a syscore shutdown callback, see > printk_kthreads_shutdown(). > > One missing piece is emergency_restart() where the kthreads are not > stopped. It might be called from several non-panic code paths, > e.g. sysrq-o, kdb_reboot(), or some watchdogs. > > Fix it by explicitly entering the emergency (atomic) mode and trying > to flush the consoles there. > > Note that printk_trigger_flush() must be used instead of pr_flush() > because the later is not safe in an atomic context. > > Reported-by: kernel test robot > Closes: https://lore.kernel.org/all/202608061008.48a1e76e-lkp@intel.com/ > Suggested-by: John Ogness > Signed-off-by: Petr Mladek JFYI, the patch has been committed into printk/linux.git, branch for-7.3-hotfix. I am going to give it a spin in linux-next and send a pull request on Friday unless any blocker appears in the meantime. Best Regards, Petr