From d901b86539efde0474129016eb7d00e4dd709461 Mon Sep 17 00:00:00 2001
Message-Id: <d901b86539efde0474129016eb7d00e4dd709461.1599166691.git.zanussi@kernel.org>
In-Reply-To: <56457dc415803c8abc5acb513ada877a79596f05.1599166690.git.zanussi@kernel.org>
References: <56457dc415803c8abc5acb513ada877a79596f05.1599166690.git.zanussi@kernel.org>
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Mon, 11 Apr 2016 16:55:02 +0200
Subject: [PATCH 168/333] tty: serial: 8250: don't take the trylock during oops
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.142-rt63.tar.xz

An oops with irqs off (panic() from irqsafe hrtimer like the watchdog
timer) will lead to a lockdep warning on each invocation and as such
never completes.
Therefore we skip the trylock in the oops case.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/tty/serial/8250/8250_port.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 20b799219826..48c9574362c5 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -3245,10 +3245,8 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 
 	serial8250_rpm_get(up);
 
-	if (port->sysrq)
+	if (port->sysrq || oops_in_progress)
 		locked = 0;
-	else if (oops_in_progress)
-		locked = spin_trylock_irqsave(&port->lock, flags);
 	else
 		spin_lock_irqsave(&port->lock, flags);
 
-- 
2.17.1

