[PATCH next v1] serial: msm_serial: disable interrupts in __msm_console_write()

[John Ogness]

__msm_console_write() assumes that interrupts are disabled, but
with threaded console printers it is possible that the write()
callback of the console is called with interrupts enabled.

Explicitly disable interrupts using local_irq_save() to preserve
the assumed context.

Reported-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Signed-off-by: John Ogness <john.ogness@xxxxxxxxxxxxx>
---
 Note: I checked the other serial drivers and this was the only
       one that assumed interrupts off for write().

 drivers/tty/serial/msm_serial.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
index 23c94b927776..e676ec761f18 100644
--- a/drivers/tty/serial/msm_serial.c
+++ b/drivers/tty/serial/msm_serial.c
@@ -1599,6 +1599,7 @@ static inline struct uart_port *msm_get_port_from_line(unsigned int line)
 static void __msm_console_write(struct uart_port *port, const char *s,
 				unsigned int count, bool is_uartdm)
 {
+	unsigned long flags;
 	int i;
 	int num_newlines = 0;
 	bool replaced = false;
@@ -1616,6 +1617,8 @@ static void __msm_console_write(struct uart_port *port, const char *s,
 			num_newlines++;
 	count += num_newlines;
 
+	local_irq_save(flags);
+
 	if (port->sysrq)
 		locked = 0;
 	else if (oops_in_progress)
@@ -1661,6 +1664,8 @@ static void __msm_console_write(struct uart_port *port, const char *s,
 
 	if (locked)
 		spin_unlock(&port->lock);
+
+	local_irq_restore(flags);
 }
 
 static void msm_console_write(struct console *co, const char *s,

base-commit: 38a288f5941ef03752887ad86f2d85442358c99a
-- 
2.30.2