8250.c: port.lock is irq-safe

serial8250_startup() doesn't disable interrupts while taking the &up->port.lock which might race against the interrupt handler serial8250_interrupt(), which when entered, will deadlock waiting for the lock to be released. Signed-off-by: Borislav Petkov <[email protected]> Tested-by: Ingo Molnar <[email protected]> Cc: Alan Cox <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
maurer · Jul 30, 2008 · c389d27 · c389d27
1 parent 5def9a3
commit c389d27
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
@@ -1885,7 +1885,7 @@ static int serial8250_startup(struct uart_port *port)
 		 * the interrupt is enabled.  Delays are necessary to
 		 * allow register changes to become visible.
 		 */
-		spin_lock(&up->port.lock);
+		spin_lock_irqsave(&up->port.lock, flags);
 		if (up->port.flags & UPF_SHARE_IRQ)
 			disable_irq_nosync(up->port.irq);
 
@@ -1901,7 +1901,7 @@ static int serial8250_startup(struct uart_port *port)
 
 		if (up->port.flags & UPF_SHARE_IRQ)
 			enable_irq(up->port.irq);
-		spin_unlock(&up->port.lock);
+		spin_unlock_irqrestore(&up->port.lock, flags);
 
 		/*
 		 * If the interrupt is not reasserted, setup a timer to