wifi: libertas: don't kill URBs in interrupt context

[ Upstream commit 7c5c2b6 ]

Serialization for the TX path was enforced by calling
usb_kill_urb()/usb_kill_anchored_urbs(), to prevent transmission before
a previous URB was completed. usb_tx_block() can be called from
interrupt context (e.g. in the HCD giveback path), so we can't always
use it to kill in-flight URBs.

Prevent sleeping during interrupt context by checking the tx_submitted
anchor for existing URBs. We now return -EBUSY, to indicate there's
a pending request.

Reported-by: syzbot+74afbb6355826ffc2239@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=74afbb6355826ffc2239
Fixes: d66676e ("wifi: libertas: fix WARNING in usb_tx_block")
Signed-off-by: Heitor Alves de Siqueira <halves@igalia.com>
Link: https://patch.msgid.link/20260313-libertas-usb-anchors-v1-2-915afbe988d7@igalia.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: hrasiq

drivers/net/wireless/marvell/libertas/if_usb.c

@@ -429,7 +429,12 @@ static int usb_tx_block(struct if_usb_card *cardp, uint8_t *payload, uint16_t nb
 		goto tx_ret;
 	}
 
-	usb_kill_anchored_urbs(&cardp->tx_submitted);
+	/* check if there are pending URBs */
+	if (!usb_anchor_empty(&cardp->tx_submitted)) {
+		lbs_deb_usbd(&cardp->udev->dev, "%s failed: pending URB\n", __func__);
+		ret = -EBUSY;
+		goto tx_ret;
+	}
 
 	usb_fill_bulk_urb(cardp->tx_urb, cardp->udev,
 			  usb_sndbulkpipe(cardp->udev,