Re: [PATCH v2] driver core: Take parent lock in async device attach

[sashiko-bot@kernel.org]

> On buses with need_parent_lock set (only USB), probe() must run with the
> parent device locked. A synchronous attach after device_add() gets this
> from the caller, e.g. usb_set_configuration() holds the udev lock while
> adding interfaces. __device_attach_async_helper() runs the probe from an
> async worker instead, where that lock isn't held, and only takes
> device_lock(dev).
> 
> With async probing enabled for the hub driver (e.g. driver_async_probe=*
> or driver_async_probe=hub), this races when a multi-TT hub is
> configured. For multi-TT hubs, hub_probe() calls
> usb_set_interface(hdev, 0, 1) to select the TT-per-port altsetting, and
> usb_set_interface() creates the endpoint devices of the interface a
> second time:
> 
>   usb_set_configuration()           async worker
> [ ... ]
> gone in 300 boots on the board and in 6000 iterations in QEMU.
> 
> Fixes: 765230b5f084 ("driver-core: add asynchronous probing support for drivers")
> Assisted-by: LLM
> Signed-off-by: Mario Peter <mario.peter@leica-geosystems.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261007131514.1260696-1-mario.peter@leica-geosystems.com?part=1