linux-kernel - [PATCH] drm/amdkfd: fix uninitialized variable use

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Date:   Thu, 15 Mar 2018 17:49:40 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     Oded Gabbay <oded.gabbay@...il.com>,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        "David (ChunMing) Zhou" <David1.Zhou@....com>,
        David Airlie <airlied@...ux.ie>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Felix Kuehling <Felix.Kuehling@....com>,
        Harish Kasiviswanathan <Harish.Kasiviswanathan@....com>,
        Kent Russell <kent.russell@....com>,
        Amber Lin <Amber.Lin@....com>, dri-devel@...ts.freedesktop.org,
        amd-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH] drm/amdkfd: fix uninitialized variable use

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@...db.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