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From: John Ogness <john.ogness@linutronix.de>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Josh Poimboeuf <jpoimboe@kernel.org>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Kefeng Wang <wangkefeng.wang@huawei.com>,
	"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
	Uros Bizjak <ubizjak@gmail.com>,
	Arnd Bergmann <arnd@arndb.de>
Subject: [PATCH printk v2 23/26] panic: Mark emergency section in warn
Date: Sun, 18 Feb 2024 20:03:23 +0106
Message-Id: <20240218185726.1994771-24-john.ogness@linutronix.de>
In-Reply-To: <20240218185726.1994771-1-john.ogness@linutronix.de>
References: <20240218185726.1994771-1-john.ogness@linutronix.de>
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From: Thomas Gleixner <tglx@linutronix.de>

Mark the full contents of __warn() as an emergency section. In
this section, the CPU will not perform console output for the
printk() calls. Instead, a flushing of the console output is
triggered when exiting the emergency section.

Co-developed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Thomas Gleixner (Intel) <tglx@linutronix.de>
---
 kernel/panic.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/panic.c b/kernel/panic.c
index 86813305510f..d30d261f9246 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -667,6 +667,8 @@ struct warn_args {
 void __warn(const char *file, int line, void *caller, unsigned taint,
 	    struct pt_regs *regs, struct warn_args *args)
 {
+	nbcon_cpu_emergency_enter();
+
 	disable_trace_on_warning();
 
 	if (file)
@@ -697,6 +699,8 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
 
 	/* Just a warning, don't kill lockdep. */
 	add_taint(taint, LOCKDEP_STILL_OK);
+
+	nbcon_cpu_emergency_exit();
 }
 
 #ifdef CONFIG_BUG
-- 
2.39.2