From: Tyrel Datwyler tyreld@linux.ibm.com
[ Upstream commit 63ffcbdad738e3d1c857027789a2273df3337624 ]
The code currently NULLs tty->driver_data in hvcs_close() with the intent of informing the next call to hvcs_open() that device needs to be reconfigured. However, when hvcs_cleanup() is called we copy hvcsd from tty->driver_data which was previoulsy NULLed by hvcs_close() and our call to tty_port_put(&hvcsd->port) doesn't actually do anything since &hvcsd->port ends up translating to NULL by chance. This has the side effect that when hvcs_remove() is called we have one too many port references preventing hvcs_destuct_port() from ever being called. This also prevents us from reusing the /dev/hvcsX node in a future hvcs_probe() and we can eventually run out of /dev/hvcsX devices.
Fix this by waiting to NULL tty->driver_data in hvcs_cleanup().
Fixes: 27bf7c43a19c ("TTY: hvcs, add tty install") Signed-off-by: Tyrel Datwyler tyreld@linux.ibm.com Link: https://lore.kernel.org/r/20200820234643.70412-1-tyreld@linux.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/hvc/hvcs.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/tty/hvc/hvcs.c b/drivers/tty/hvc/hvcs.c index ee0604cd9c6b2..0c498b20d8cb5 100644 --- a/drivers/tty/hvc/hvcs.c +++ b/drivers/tty/hvc/hvcs.c @@ -1218,13 +1218,6 @@ static void hvcs_close(struct tty_struct *tty, struct file *filp)
tty_wait_until_sent(tty, HVCS_CLOSE_WAIT);
- /* - * This line is important because it tells hvcs_open that this - * device needs to be re-configured the next time hvcs_open is - * called. - */ - tty->driver_data = NULL; - free_irq(irq, hvcsd); return; } else if (hvcsd->port.count < 0) { @@ -1239,6 +1232,13 @@ static void hvcs_cleanup(struct tty_struct * tty) { struct hvcs_struct *hvcsd = tty->driver_data;
+ /* + * This line is important because it tells hvcs_open that this + * device needs to be re-configured the next time hvcs_open is + * called. + */ + tty->driver_data = NULL; + tty_port_put(&hvcsd->port); }