Re: [PATCH] Fix dereferencing freed memory 'fw'

From: Heikki Krogerus
Date: Mon Sep 23 2024 - 04:20:38 EST


Hi Dipendra,

Thanks for the patch. You forgot the susbsytem and driver from your
subject line:
https://docs.kernel.org/process/submitting-patches.html#the-canonical-patch-format

On Sun, Sep 22, 2024 at 10:52:11AM +0000, Dipendra Khadka wrote:
> smatch reported dereferencing freed memory as below:
> '''
> drivers/usb/typec/tipd/core.c:1196 tps6598x_apply_patch() error: dereferencing freed memory 'fw'
> '''
>
> Invoking release_firware(fw) just after checking ret.
>
> Signed-off-by: Dipendra Khadka <kdipendra88@xxxxxxxxx>

This is a use-after-free case, so please add the Fixes tag:

Fixes: 916b8e5fa73d ("usb: typec: tipd: add error log to provide firmware name and size")

> ---
> drivers/usb/typec/tipd/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/typec/tipd/core.c b/drivers/usb/typec/tipd/core.c
> index ea768b19a7f1..eb5596e3406a 100644
> --- a/drivers/usb/typec/tipd/core.c
> +++ b/drivers/usb/typec/tipd/core.c
> @@ -1191,11 +1191,11 @@ static int tps6598x_apply_patch(struct tps6598x *tps)
> dev_info(tps->dev, "Firmware update succeeded\n");
>
> release_fw:
> - release_firmware(fw);
> if (ret) {
> dev_err(tps->dev, "Failed to write patch %s of %zu bytes\n",
> firmware_name, fw->size);
> }
> + release_firmware(fw);
>
> return ret;
> };
> --
> 2.43.0

thanks,

--
heikki