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From: Doug Anderson <dianders@chromium.org>
Date: Fri, 26 Jan 2024 09:47:23 -0800
Message-ID: <CAD=FV=UzGcneoL1d-DDXVugAeq2+YLCKrq8-5B7TfVAAKgF=SQ@mail.gmail.com>
Subject: Re: [PATCH] HID: i2c-hid-of: fix NULL-deref on failed power up
To: Johan Hovold <johan+linaro@kernel.org>
Cc: Jiri Kosina <jikos@kernel.org>, Benjamin Tissoires <benjamin.tissoires@redhat.com>, 
	linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, 
	stable@vger.kernel.org
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Hi,

On Fri, Jan 26, 2024 at 9:10=E2=80=AFAM Johan Hovold <johan+linaro@kernel.o=
rg> wrote:
>
> A while back the I2C HID implementation was split in an ACPI and OF
> part, but the new OF driver never initialises the client pointer which
> is dereferenced on power-up failures.
>
> Fixes: b33752c30023 ("HID: i2c-hid: Reorganize so ACPI and OF are separat=
e modules")
> Cc: stable@vger.kernel.org      # 5.12
> Cc: Douglas Anderson <dianders@chromium.org>
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
>  drivers/hid/i2c-hid/i2c-hid-of.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid-of.c b/drivers/hid/i2c-hid/i2c-h=
id-of.c
> index c4e1fa0273c8..8be4d576da77 100644
> --- a/drivers/hid/i2c-hid/i2c-hid-of.c
> +++ b/drivers/hid/i2c-hid/i2c-hid-of.c
> @@ -87,6 +87,7 @@ static int i2c_hid_of_probe(struct i2c_client *client)
>         if (!ihid_of)
>                 return -ENOMEM;
>
> +       ihid_of->client =3D client;

Good catch and thanks for the fix. FWIW, I'd be OK w/

Reviewed-by: Douglas Anderson <dianders@chromium.org>

That being said, I'd be even happier if you simply removed the
"client" from the structure and removed the error printout.
regulator_bulk_enable() already prints error messages when a failure
happens and thus the error printout is redundant and wastes space.

-Doug