[PATCH 2/2] usb: gadget: f_mass_storage: ignore class requests while inactive

[Keisuke Tsukuda <catnyaaan@outlook.com>]

SET_CONFIGURATION is handled asynchronously by the mass-storage thread.
A class request can arrive after the composite core selects the function
but before the thread installs common->fsg, or while the function is being
disabled.

fsg_setup() already rejects this state with -EOPNOTSUPP, but checking it
through fsg_is_set() also emits a warning. Check the active function
directly so normal requests during a configuration transition are rejected
without hiding fsg_is_set() warnings from other internal paths.

Fixes: 8876f5e7d3b2 ("USB: gadget: f_mass_storage: added eject callback")
Reported-by: syzbot+d31109047baed8f3b590@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=d31109047baed8f3b590
Signed-off-by: Keisuke Tsukuda <tkdkei@outlook.jp>
---
 drivers/usb/gadget/function/f_mass_storage.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
index a50743c..52d486a 100644
--- a/drivers/usb/gadget/function/f_mass_storage.c
+++ b/drivers/usb/gadget/function/f_mass_storage.c
@@ -463,7 +463,7 @@ static int fsg_setup(struct usb_function *f,
 	u16			w_value = le16_to_cpu(ctrl->wValue);
 	u16			w_length = le16_to_cpu(ctrl->wLength);
 
-	if (!fsg_is_set(fsg->common))
+	if (!fsg->common->fsg)
 		return -EOPNOTSUPP;
 
 	++fsg->common->ep0_req_tag;	/* Record arrival of a new request */
-- 
2.50.1 (Apple Git-155)