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

["Vlastimil Babka (SUSE)" <vbabka@kernel.org>]

On 7/31/26 19:36, Jeff Johnson wrote:
> On 7/29/2026 1:04 AM, syzbot wrote:
>> From: Slawomir Stepien <sst@poczta.fm>
>> 
>> 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 <sst@poczta.fm>
> 
> 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).
> 
> +workflows list

The original mail [1] has this at the bottom:

> See https://goo.gle/syzbot-ai-patches for information about AI-generated
patches.

Where it says:

> Patches mailed to the kernel mailing lists were reviewed and Signed-off-by
by at least one human developer in accordance with AI Coding Assistants
guidelines.

Since From: and S-o-b: refers to a human developer, and there's Assisted-by:
it seems to be according to the rules. The "From: syzbot" seems to be just a
sending mechanism, that wouldn't even make it to the git commit log.

[1]
https://lore.kernel.org/all/0720e3ad-d98e-47d7-89af-4d22416b0fbc@mail.kernel.org/