[PATCH v3 8/8] serial: exar: fix: fix crash during shutdown if setup fails

[Parker Newman]

From: Parker Newman <pnewman@xxxxxxxxxxxxxxx>

If a port fails to register with serial8250_register_8250_port() the
kernel can crash when shutting down or module removal.

This is because "priv->line[i]" will be set to a negative error code
and in the exar_pci_remove() function serial8250_unregister_port() is
called without checking if the "priv->line[i]" value is valid.

Signed-off-by: Parker Newman <pnewman@xxxxxxxxxxxxxxx>
---
 drivers/tty/serial/8250/8250_exar.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
index 501b9f3e9c89..f5a395ed69d1 100644
--- a/drivers/tty/serial/8250/8250_exar.c
+++ b/drivers/tty/serial/8250/8250_exar.c
@@ -1671,7 +1671,8 @@ static void exar_pci_remove(struct pci_dev *pcidev)
 	unsigned int i;

 	for (i = 0; i < priv->nr; i++)
-		serial8250_unregister_port(priv->line[i]);
+		if (priv->line[i] >= 0)
+			serial8250_unregister_port(priv->line[i]);

 	/* Ensure that every init quirk is properly torn down */
 	if (priv->board->exit)
--
2.43.2