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From:   Ray Chi <raychi@google.com>
Date:   Thu, 4 Mar 2021 00:02:51 +0800
Message-ID: <CAPBYUsCPj12enyMp9AMzFEAgd5MdKh7dYN5DNFpZwofBYnjG8A@mail.gmail.com>
Subject: Re: [PATCH] usb: dwc3: Fix dereferencing of null dwc->usb_psy
To:     Colin King <colin.king@canonical.com>
Cc:     Felipe Balbi <balbi@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, kernel-janitors@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Wed, Mar 3, 2021 at 6:00 PM Colin King <colin.king@canonical.com> wrote:
>
> From: Colin Ian King <colin.king@canonical.com>
>
> Currently the null check logic on dwc->usb_psy is inverted as it allows
> calls to power_supply_put with a null dwc->usb_psy causing a null
> pointer dereference. Fix this by removing the ! operator.
>
> Addresses-Coverity: ("Dereference after null check")
> Fixes: 59fa3def35de ("usb: dwc3: add a power supply for current control")

Acked-by: Ray Chi <raychi@google.com>

> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/usb/dwc3/core.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index d15f065849cd..94fdbe502ce9 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1628,7 +1628,7 @@ static int dwc3_probe(struct platform_device *pdev)
>  assert_reset:
>         reset_control_assert(dwc->reset);
>
> -       if (!dwc->usb_psy)
> +       if (dwc->usb_psy)
>                 power_supply_put(dwc->usb_psy);
>
>         return ret;
> @@ -1653,7 +1653,7 @@ static int dwc3_remove(struct platform_device *pdev)
>         dwc3_free_event_buffers(dwc);
>         dwc3_free_scratch_buffers(dwc);
>
> -       if (!dwc->usb_psy)
> +       if (dwc->usb_psy)
>                 power_supply_put(dwc->usb_psy);
>
>         return 0;
> --
> 2.30.0
>

Thanks for fixing this bug!

Regards,
Ray