6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jun Yan <jerrysteve1101@xxxxxxxxx>
commit 7a3d76a0b60b3f6fc3375e4de2174bab43f64545 upstream.
Fix the regression introduced by commit d8c6edfa3f4e ("USB:
usblp: don't call usb_set_interface if there's a single alt"),
which causes that unsupported protocols can also be set via
ioctl when the num_altsetting of the device is 1.
Move the check for protocol support to the earlier stage.
Fixes: d8c6edfa3f4e ("USB: usblp: don't call usb_set_interface if there's a single alt")
Cc: stable <stable@xxxxxxxxxx>
Signed-off-by: Jun Yan <jerrysteve1101@xxxxxxxxx>
Link: https://lore.kernel.org/r/20241212143852.671889-1-jerrysteve1101@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/class/usblp.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -1337,11 +1337,12 @@ static int usblp_set_protocol(struct usb
if (protocol < USBLP_FIRST_PROTOCOL || protocol > USBLP_LAST_PROTOCOL)
return -EINVAL;
+ alts = usblp->protocol[protocol].alt_setting;
+ if (alts < 0)
+ return -EINVAL;
+
/* Don't unnecessarily set the interface if there's a single alt. */
if (usblp->intf->num_altsetting > 1) {
- alts = usblp->protocol[protocol].alt_setting;
- if (alts < 0)
- return -EINVAL;
r = usb_set_interface(usblp->dev, usblp->ifnum, alts);
if (r < 0) {
printk(KERN_ERR "usblp: can't set desired altsetting %d on interface %d\n",
