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Date:   Mon, 24 Jan 2022 10:54:59 +0200
From:   Heikki Krogerus <heikki.krogerus@linux.intel.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Robert =?utf-8?B?xZp3acSZY2tp?= <robert@swiecki.net>,
        Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Subject: Re: [PATCH] usb: typec: Only attempt to link USB ports if there is
 fwnode
Message-ID: <Ye5pY97VOb4TdZjH@kuha.fi.intel.com>
References: <20220118093627.74098-1-heikki.krogerus@linux.intel.com>
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On Tue, Jan 18, 2022 at 12:36:27PM +0300, Heikki Krogerus wrote:
> The code that creates the links to the USB ports attached to
> a connector inside the system assumed that the ACPI nodes
> (fwnodes) always exist for the connectors, but it can not do
> that.
> 
> There is no guarantee that every USB Type-C connector has
> ACPI device node representing it in the ACPI tables, and
> even if there are the nodes in the ACPI tables, the _STA
> method in those nodes may still return 0 (which means the
> device does not exist from ACPI PoW).
> 
> This fixes NULL pointer dereference that happens if the
> nodes are missing.

I'll resend this togher wit the other fix.

thanks,

> Reported-and-tested-by: Robert Święcki <robert@swiecki.net>
> Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
> Fixes: 730b49aac426 ("usb: typec: port-mapper: Convert to the component framework")
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
> Hi guys,
> 
> Mikhail, I got confirmation from Robert that the patch fixes the
> issue.
> 
> thanks,
> ---
>  drivers/usb/typec/port-mapper.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/port-mapper.c b/drivers/usb/typec/port-mapper.c
> index 07d307418b470..b6e0c6acc628c 100644
> --- a/drivers/usb/typec/port-mapper.c
> +++ b/drivers/usb/typec/port-mapper.c
> @@ -56,6 +56,9 @@ int typec_link_ports(struct typec_port *con)
>  {
>  	struct each_port_arg arg = { .port = con, .match = NULL };
>  
> +	if (!has_acpi_companion(&con->dev))
> +		return 0;
> +
>  	bus_for_each_dev(&acpi_bus_type, NULL, &arg, typec_port_match);
>  
>  	/*
> @@ -74,5 +77,6 @@ int typec_link_ports(struct typec_port *con)
>  
>  void typec_unlink_ports(struct typec_port *con)
>  {
> -	component_master_del(&con->dev, &typec_aggregate_ops);
> +	if (has_acpi_companion(&con->dev))
> +		component_master_del(&con->dev, &typec_aggregate_ops);
>  }
> -- 
> 2.34.1

-- 
heikki