This is a note to let you know that I've just added the patch titled
usb: gadget: f_fs: Fix unbalanced spinlock in __ffs_ep0_queue_wait
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-gadget-f_fs-fix-unbalanced-spinlock-in-__ffs_ep0.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 156d91ac8d95d7815f60689a17e7eb5e9886268c
Author: Udipto Goswami <quic_ugoswami@xxxxxxxxxxx>
Date: Tue Jan 24 14:41:49 2023 +0530
usb: gadget: f_fs: Fix unbalanced spinlock in __ffs_ep0_queue_wait
[ Upstream commit 921deb9da15851425ccbb6ee409dc2fd8fbdfe6b ]
__ffs_ep0_queue_wait executes holding the spinlock of &ffs->ev.waitq.lock
and unlocks it after the assignments to usb_request are done.
However in the code if the request is already NULL we bail out returning
-EINVAL but never unlocked the spinlock.
Fix this by adding spin_unlock_irq &ffs->ev.waitq.lock before returning.
Fixes: 6a19da111057 ("usb: gadget: f_fs: Prevent race during ffs_ep0_queue_wait")
Reviewed-by: John Keeping <john@xxxxxxxxxxxx>
Signed-off-by: Udipto Goswami <quic_ugoswami@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230124091149.18647-1-quic_ugoswami@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index c9145ee95956..f975111bd974 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -279,8 +279,10 @@ static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
struct usb_request *req = ffs->ep0req;
int ret;
- if (!req)
+ if (!req) {
+ spin_unlock_irq(&ffs->ev.waitq.lock);
return -EINVAL;
+ }
req->zero = len < le16_to_cpu(ffs->ev.setup.wLength);
