From 9e370d2c9f59a63dda0ced3ecd1b55498d97c449 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Fri, 8 Jan 2016 15:33:50 -0500 Subject: [PATCH] serial-uartlite: fix missing locking in isr 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 Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/uartlite.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c index c249aee887d2..ee2e8efdea4a 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); -- 2.45.2