Re: [PATCH v2 1/4] ACPI: NFIT: core: Fix possible NULL pointer dereference

[Dave Jiang]

On 6/3/26 10:56 AM, Rafael J. Wysocki wrote:
> From: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>
> 
> After commit 9b311b7313d6 ("ACPI: NFIT: Install Notify() handler before
> getting NFIT table"), acpi_nfit_probe() installs an ACPI notify handler
> for the NFIT device before checking the presence of the NFIT table.  If
> that table is not there, 0 is returned without allocating the acpi_desc
> object and setting the driver data pointer of the NFIT device.  If the
> platform firmware triggers an NFIT_NOTIFY_UC_MEMORY_ERROR notification
> on the NFIT device at that point, acpi_nfit_uc_error_notify() will
> dereference a NULL pointer.
> 
> Prevent that from occurring by adding an acpi_desc check against NULL
> to acpi_nfit_uc_error_notify().
> 
> Fixes: 9b311b7313d6 ("ACPI: NFIT: Install Notify() handler before getting NFIT table")
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Cc: All applicable <stable@xxxxxxxxxxxxxxx>

Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>


> ---
>  drivers/acpi/nfit/core.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
> index 5cab62f618c8..8024cd3cad14 100644
> --- a/drivers/acpi/nfit/core.c
> +++ b/drivers/acpi/nfit/core.c
> @@ -3442,6 +3442,9 @@ static void acpi_nfit_uc_error_notify(struct device *dev, acpi_handle handle)
>  {
>  	struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(dev);
>  
> +	if (!acpi_desc)
> +		return;
> +
>  	if (acpi_desc->scrub_mode == HW_ERROR_SCRUB_ON)
>  		acpi_nfit_ars_rescan(acpi_desc, ARS_REQ_LONG);
>  	else