Re: [PATCH v3] usb: typec: tcpm: Add IS_ERR_OR_NULL check for port->partner

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Aug 16, 2023 at 08:30:51AM +0000, Jimmy Hu wrote:
> port->partner may be an error or NULL. This will cause a NULL pointer
> dereference as below.
> 
> [91222.095236][  T319] typec port0: failed to register partner (-17)
> ...
> [91225.061491][  T319] Unable to handle kernel NULL pointer dereference
> at virtual address 000000000000039f
> [91225.274642][  T319] pc : tcpm_pd_data_request+0x310/0x13fc
> [91225.274646][  T319] lr : tcpm_pd_data_request+0x298/0x13fc
> [91225.308067][  T319] Call trace:
> [91225.308070][  T319]  tcpm_pd_data_request+0x310/0x13fc
> [91225.308073][  T319]  tcpm_pd_rx_handler+0x100/0x9e8
> [91225.355900][  T319]  kthread_worker_fn+0x178/0x58c
> [91225.355902][  T319]  kthread+0x150/0x200
> [91225.355905][  T319]  ret_from_fork+0x10/0x30
> 
> Add a check for port->partner to avoid dereferencing a NULL pointer.
> 
> Fixes: 5e1d4c49fbc8 ("usb: typec: tcpm: Determine common SVDM Version")
> Signed-off-by: Jimmy Hu <hhhuuu@google.com>
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 5639b9a1e0bf..ca9b1f3a38bc 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -1625,6 +1625,9 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
>  			if (PD_VDO_VID(p[0]) != USB_SID_PD)
>  				break;
>  
> +			if (IS_ERR_OR_NULL(port->partner))
> +				break;
> +
>  			if (PD_VDO_SVDM_VER(p[0]) < svdm_version) {
>  				typec_partner_set_svdm_version(port->partner,
>  							       PD_VDO_SVDM_VER(p[0]));
> -- 
> 2.41.0.694.ge786442a9b-goog
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
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  Please read the section entitled "The canonical patch format" in the
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  needs to be done here to properly describe this.

If you wish to discuss this problem further, or you have questions about
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thanks,

greg k-h's patch email bot