From: John Ogness john.ogness@linutronix.de
[ Upstream commit 25614735a647693c1260f253dc3ab32127697806 ]
omap8250_irq() accesses UART_IER. This register is modified twice by each console write (serial8250_console_write()) under the port lock. omap8250_irq() must also take the port lock to guanentee synchronized access to UART_IER.
Since the port lock is already being taken for the stop_rx() callback and since it is safe to call cancel_delayed_work() while holding the port lock, simply extend the port lock region to include UART_IER access.
Fixes: 1fe0e1fa3209 ("serial: 8250_omap: Handle optional overrun-throttle-ms property") Signed-off-by: John Ogness john.ogness@linutronix.de Reviewed-by: Tony Lindgren tony@atomide.com Link: https://lore.kernel.org/r/20230525093159.223817-8-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/8250/8250_omap.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c index 7ecd2d379292b..17a230281ebe0 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -639,17 +639,18 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id) if ((lsr & UART_LSR_OE) && up->overrun_backoff_time_ms > 0) { unsigned long delay;
+ /* Synchronize UART_IER access against the console. */ + spin_lock(&port->lock); up->ier = port->serial_in(port, UART_IER); if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) { - spin_lock(&port->lock); port->ops->stop_rx(port); - spin_unlock(&port->lock); } else { /* Keep restarting the timer until * the input overrun subsides. */ cancel_delayed_work(&up->overrun_backoff); } + spin_unlock(&port->lock);
delay = msecs_to_jiffies(up->overrun_backoff_time_ms); schedule_delayed_work(&up->overrun_backoff, delay);