[lvc-project] [PATCH v2 2/2] HID: usbhid: free unsent raw output reports in usbhid_stop()

[Dmitry Antipov]

When HID device is stalled or disconnected, there might be an
unsent (i.e. never passed via 'hid_submit_out()') output reports.
So free their raw buffers in 'usbhid_stop()' to avoid memory leaks.

This is a companion of commit f7744fa16b96 ("HID: usbhid: free
raw_report buffers in usbhid_stop") and inspired by that one.

Reported-by: syzbot+e2c057ea576d2644e2be at syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=e2c057ea576d2644e2be
Fixes: c500c9714011 ("HID: hid, make parsing event driven")
Assisted-by: Sashiko:gemini/gemini-3.1-pro-preview
Signed-off-by: Dmitry Antipov <dmantipov at yandex.ru>
---
v2: adjust loop to match actual FIFO size and tweak commit message
---
 drivers/hid/usbhid/hid-core.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index 96b0181cf819..60662616fd2a 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -1253,6 +1253,14 @@ static void usbhid_stop(struct hid_device *hid)
 		usbhid->ctrltail = (usbhid->ctrltail + 1) &
 			(HID_CONTROL_FIFO_SIZE - 1);
 	}
+
+	while (usbhid->outtail != usbhid->outhead) {
+		kfree(usbhid->out[usbhid->outtail].raw_report);
+		usbhid->out[usbhid->outtail].raw_report = NULL;
+
+		usbhid->outtail = (usbhid->outtail + 1) &
+			(HID_OUTPUT_FIFO_SIZE - 1);
+	}
 	spin_unlock_irq(&usbhid->lock);
 
 	usb_kill_urb(usbhid->urbin);
-- 
2.55.0