[PATCH] serial-uartlite: fix missing locking in isr
From: Rich Felker <dalias@libc.org>
Date: 2016-01-08 20:33:58
Also in:
lkml
Subsystem:
the rest, tty layer and serial drivers, xilinx uartlite serial driver · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby, Peter Korsgaard
From: Rich Felker <dalias@libc.org> 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@libc.org> ---
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);