Re: [PATCH] wifi: zd1211rw: reject secondary interfaces to prevent conflicts

[Jeff Johnson]

On 7/29/2026 1:04 AM, syzbot wrote:
> From: Slawomir Stepien <sst@xxxxxxxxx>
> 
> 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@xxxxxxxxxxxxxxxxxxxxxxxxx
> 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 <sst@xxxxxxxxx>

E-mail from syzbot but SOB from a human?

I read the trailer, but this seems to violate:
https://docs.kernel.org/process/coding-assistants.html

Namely:
AI agents MUST NOT add Signed-off-by tags. Only humans can legally certify the
Developer Certificate of Origin (DCO).

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