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Commit 9e370d2c authored by Rich Felker's avatar Rich Felker Committed by Greg Kroah-Hartman
Browse files

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: default avatarRich Felker <dalias@libc.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7cdcc29e

drivers/tty/serial/uartlite.c

+4 −0
Original line number Diff line number Diff line
@@ -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);