The zd1211rw driver is designed for single-function Wi-Fi dongles and hardcodes its USB endpoints. When a malformed USB device exposes multiple interfaces that match the driver's device ID, the driver blindly binds to all of them. During probe(), the driver calls usb_reset_device(), which iterates over all interfaces and invokes the pre_reset() callback for each bound interface. Since multiple interfaces are bound to zd1211rw, pre_reset() is called sequentially for each instance, acquiring their respective &mac->chip.mutex. Because all instances initialize their mutexes with the same lock class, lockdep detects a task acquiring a lock of the same class it already holds and flags it as a possible recursive deadlock: WARNING: possible recursive locking detected kworker/0:1/11 is trying to acquire lock: ffff88810371dde0 (&chip->mutex){+.+.}-{4:4}, at: zd_chip_disable_rxtx+0x20/0x50 drivers/net/wireless/zydas/zd1211rw/zd_chip.c:1465 but task is already holding lock: ffff8881138ddde0 (&chip->mutex){+.+.}-{4:4}, at: pre_reset+0x28c/0x380 drivers/net/wireless/zydas/zd1211rw/zd_usb.c:1505 Fix this by explicitly rejecting secondary interfaces (bInterfaceNumber != 0) during probe(). This ensures that only a single instance of the driver binds to the device, eliminating the recursive locking scenario. Fixes: e85d0918b54f ("[PATCH] ZyDAS ZD1211 USB-WLAN driver") Assisted-by: Gemini:gemini-3.5-flash Gemini:gemini-3.1-pro-preview syzbot Reported-by: syzbot+0ec3d1a6cf1fbe79c153@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=0ec3d1a6cf1fbe79c153 Link: https://syzkaller.appspot.com/ai_job?id=00724ef7-fd77-4cde-9779-895b8f63c2f6 Signed-off-by: Slawomir Stepien --- v2: * Fix the style of the block comment v1: * https://lore.kernel.org/all/0720e3ad-d98e-47d7-89af-4d22416b0fbc@mail.kernel.org/T/ --- drivers/net/wireless/zydas/zd1211rw/zd_usb.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/net/wireless/zydas/zd1211rw/zd_usb.c b/drivers/net/wireless/zydas/zd1211rw/zd_usb.c index 966d8ccb0dbc..98102c663434 100644 --- a/drivers/net/wireless/zydas/zd1211rw/zd_usb.c +++ b/drivers/net/wireless/zydas/zd1211rw/zd_usb.c @@ -1353,6 +1353,14 @@ static int probe(struct usb_interface *intf, const struct usb_device_id *id) struct zd_usb *usb; struct ieee80211_hw *hw = NULL; + /* + * ZD1211 devices are single-function. Reject secondary interfaces + * to prevent multiple instances from conflicting on hardcoded endpoints + * and triggering recursive locking warnings. + */ + if (intf->cur_altsetting->desc.bInterfaceNumber != 0) + return -ENODEV; + print_id(udev); if (id->driver_info & DEVICE_INSTALLER) -- 2.55.0