From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rich Felker Subject: [PATCH] serial-uartlite: fix missing locking in isr Date: Fri, 8 Jan 2016 15:33:50 -0500 Message-ID: <20160108203350.GA23919@brightrain.aerifal.cx> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: Peter Korsgaard Cc: linux-serial@vger.kernel.org, Greg Kroah-Hartman , Jiri Slaby , linux-kernel@vger.kernel.org List-Id: linux-serial@vger.kernel.org From: Rich Felker 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 --- 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);