From: Rich Felker <dalias@xxxxxxxx>
The uartlite driver suffers from missing/duplicate/corrupted character
data when the interrupt handler runs concurrently with access to the
device from another cpu. Take the port spinlock to exclude concurrent
access.
Signed-off-by: Rich Felker <dalias@xxxxxxxx>
---
diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
index 189f52e..3b818ec 100644
--- a/drivers/tty/serial/uartlite.c
+++ b/drivers/tty/serial/uartlite.c
@@ -194,7 +194,9 @@ static irqreturn_t ulite_isr(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
int busy, n = 0;
+ unsigned long flags;
+ spin_lock_irqsave(&port->lock, flags);
do {
int stat = uart_in32(ULITE_STATUS, port);
busy = ulite_receive(port, stat);
@@ -202,6 +204,8 @@ static irqreturn_t ulite_isr(int irq, void *dev_id)
n++;
} while (busy);
+ spin_unlock_irqrestore(&port->lock, flags);
+
/* work done? */
if (n > 1) {
tty_flip_buffer_push(&port->state->port);
--
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