From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-rt-users@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de,
Steven Rostedt <rostedt@goodmis.org>
Subject: [PATCH RT] tty: serial: 8250: don't take the trylock during oops
Date: Tue, 12 Apr 2016 09:16:42 +0200 [thread overview]
Message-ID: <20160412071642.GA20685@linutronix.de> (raw)
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, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 5568d70eee0c..138b1b985063 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2850,9 +2850,9 @@ 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 || in_kdb_printk())
+ else if (in_kdb_printk())
locked = spin_trylock_irqsave(&port->lock, flags);
else
spin_lock_irqsave(&port->lock, flags);
--
2.8.0.rc3
reply other threads:[~2016-04-12 7:16 UTC|newest]
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