[PATCH 5.4 030/156] usb: gadget: f_fs: Fix unbalanced spinlock in __ffs_ep0_queue_wait

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From: Udipto Goswami <quic_ugoswami@xxxxxxxxxxx>

[ 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>
---
 drivers/usb/gadget/function/f_fs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 431ab6d07497..5fe749036773 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -278,8 +278,10 @@ 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);
 
-- 
2.39.0






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