linux-kernel - Re: [PATCH] spmi: Add check for remove callback in spmi_drv

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Message-ID: <Y5hqMFw0xl6lmJYL@kroah.com>
Date:   Tue, 13 Dec 2022 13:04:00 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Jishnu Prakash <quic_jprakash@...cinc.com>
Cc:     agross@...nel.org, bjorn.andersson@...aro.org,
        devicetree@...r.kernel.org, robh+dt@...nel.org,
        linus.walleij@...aro.org, quic_kamalw@...cinc.com,
        quic_jestar@...cinc.com, sboyd@...nel.org,
        quic_subbaram@...cinc.com, quic_collinsd@...cinc.com,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-arm-msm-owner@...r.kernel.org
Subject: Re: [PATCH] spmi: Add check for remove callback in spmi_drv_remove
 API

On Sun, Dec 04, 2022 at 02:53:00PM +0530, Jishnu Prakash wrote:
> Add a check for remove callback presence before calling it for a
> spmi driver, to avoid NULL pointer dereference error if remove callback
> has not been specified for that SPMI driver.
> 
> Signed-off-by: Jishnu Prakash <quic_jprakash@...cinc.com>
> ---
>  drivers/spmi/spmi.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/spmi/spmi.c b/drivers/spmi/spmi.c
> index a456ce5..6b34356 100644
> --- a/drivers/spmi/spmi.c
> +++ b/drivers/spmi/spmi.c
> @@ -350,7 +350,8 @@ static void spmi_drv_remove(struct device *dev)
>  	const struct spmi_driver *sdrv = to_spmi_driver(dev->driver);
>  
>  	pm_runtime_get_sync(dev);
> -	sdrv->remove(to_spmi_device(dev));
> +	if (sdrv->remove)
> +		sdrv->remove(to_spmi_device(dev));
>  	pm_runtime_put_noidle(dev);
>  
>  	pm_runtime_disable(dev);

What in-kernel spmi driver does not have a remove function set that
requires this change?

thanks,

greg k-h