[PATCH 5.4 046/154] drm/gma500: Add NULL check for pci_gfx_root in mid_get_vbt_data()

Greg Kroah-Hartman
2025-04-08T12:04:18Z

From: Ivan Abramov <i.abramov@mt-integration.ru>

[ Upstream commit 9af152dcf1a06f589f44a74da4ad67e365d4db9a ]

Since pci_get_domain_bus_and_slot() can return NULL, add NULL check for
pci_gfx_root in the mid_get_vbt_data().

This change is similar to the checks implemented in mid_get_fuse_settings()
and mid_get_pci_revID(), which were introduced by commit 0cecdd818cd7
("gma500: Final enables for Oaktrail") as "additional minor
bulletproofing".

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: f910b411053f ("gma500: Add the glue to the various BIOS and firmware interfaces")
Signed-off-by: Ivan Abramov <i.abramov@mt-integration.ru>
Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250306112046.17144-1-i.abramov@mt-integration.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/gma500/mid_bios.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/gma500/mid_bios.c b/drivers/gpu/drm/gma500/mid_bios.c
index 8ab44fec4bfa4..b76b86278e0e3 100644
--- a/drivers/gpu/drm/gma500/mid_bios.c
+++ b/drivers/gpu/drm/gma500/mid_bios.c
@@ -277,6 +277,11 @@ static void mid_get_vbt_data(struct drm_psb_private *dev_priv)
0, PCI_DEVFN(2, 0));
int ret = -1;

+ if (pci_gfx_root == NULL) {
+ WARN_ON(1);
+ return;
+ }
+
/* Get the address of the platform config vbt */
pci_read_config_dword(pci_gfx_root, 0xFC, &addr);
pci_dev_put(pci_gfx_root);
--
2.39.5