[PATCH] drm/amdkfd: fix uninitialized variable use

[PATCH] drm/amdkfd: fix uninitialized variable use

[Arnd Bergmann]

When CONFIG_ACPI is disabled, we never initialize the acpi_table
structure in kfd_create_crat_image_virtual:

drivers/gpu/drm/amd/amdkfd/kfd_crat.c: In function 'kfd_create_crat_image_virtual':
drivers/gpu/drm/amd/amdkfd/kfd_crat.c:888:40: error: 'acpi_table' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The undefined behavior also happens for any other acpi_get_table()
failure, but then the compiler can't warn about it.

This adds an error check that prevents the structure from
being used in error, avoiding both the undefined behavior and
the warning about it.

Fixes: 520b8fb755cc ("drm/amdkfd: Add topology support for CPUs")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/amd/amdkfd/kfd_crat.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_crat.c b/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
index 7493f47e7fe1..d85112224f1d 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
@@ -882,7 +882,7 @@ static int kfd_create_vcrat_image_cpu(void *pcrat_image, size_t *size)
 	crat_table->length = sizeof(struct crat_header);
 
 	status = acpi_get_table("DSDT", 0, &acpi_table);
-	if (status == AE_NOT_FOUND)
+	if (status != AE_OK)
 		pr_warn("DSDT table not found for OEM information\n");
 	else {
 		crat_table->oem_revision = acpi_table->revision;
-- 
2.9.0

Re: [PATCH] drm/amdkfd: fix uninitialized variable use

[Oded Gabbay]

On Thu, Mar 15, 2018 at 6:49 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> When CONFIG_ACPI is disabled, we never initialize the acpi_table
> structure in kfd_create_crat_image_virtual:
>
> drivers/gpu/drm/amd/amdkfd/kfd_crat.c: In function 'kfd_create_crat_image_virtual':
> drivers/gpu/drm/amd/amdkfd/kfd_crat.c:888:40: error: 'acpi_table' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>
> The undefined behavior also happens for any other acpi_get_table()
> failure, but then the compiler can't warn about it.
>
> This adds an error check that prevents the structure from
> being used in error, avoiding both the undefined behavior and
> the warning about it.
>
> Fixes: 520b8fb755cc ("drm/amdkfd: Add topology support for CPUs")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_crat.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_crat.c b/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
> index 7493f47e7fe1..d85112224f1d 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
> @@ -882,7 +882,7 @@ static int kfd_create_vcrat_image_cpu(void *pcrat_image, size_t *size)
>         crat_table->length = sizeof(struct crat_header);
>
>         status = acpi_get_table("DSDT", 0, &acpi_table);
> -       if (status == AE_NOT_FOUND)
> +       if (status != AE_OK)
>                 pr_warn("DSDT table not found for OEM information\n");
>         else {
>                 crat_table->oem_revision = acpi_table->revision;
> --
> 2.9.0
>

Thanks!
Applied to -next
Oded