Re: [PATCH 13/19] usb: typec: anx7411: zero on-stack alt mode descriptors

[sashiko-bot@kernel.org]

> From: Josef Bacik <josef@toxicpanda.com>
> 
> typec_port_register_altmodes() and anx7411_typec_register_altmode() fill a
> struct typec_altmode_desc on the stack member by member: svid, vdo, mode.
> typec_register_altmode() reads three more members:
> 
>  - inactive: a port alternate mode is registered with active = !inactive.
>    If the byte of stack garbage is not 0, the mode starts disabled and
>    typec_altmode_enter() refuses it with -EPERM until somebody writes to
>    the "active" attribute of the port;
>  - mode_selection: the DisplayPort and Thunderbolt drivers enter the mode
>    on their own only if it is false. For the partner alternate modes of
>    anx7411, garbage there means that the mode is never entered;
>  - roles: decides what supported_roles of the port alternate mode shows.
> 
> typec_port_register_altmodes() is what tcpm and anx7411 register the
> alternate modes of their ports with.
> CONFIG_INIT_STACK_ALL_ZERO=y hides the problem.
> 
> Fixes: 183b194d8fb6 ("usb: typec: Make active on port altmode writable")
> Fixes: be727d400066 ("usb: typec: Introduce mode_selection bit")
> Fixes: 7b458a4c5d73 ("usb: typec: Add typec_port_register_altmodes()")
> Cc: stable <stable@kernel.org>
> Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Cc: Benson Leung <bleung@chromium.org>
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261027-llm-usb-v1-0-b9751ddb9c7c@linuxfoundation.org?part=13