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Srinivasan Shanmugam 0563d172b6 drm/amd/display: Fix dereference-before-check for dc_link
The function dereferences amdgpu_dm_connector->dc_link early to
initialize verified_link_cap and dc, but later still checks
amdgpu_dm_connector->dc_link for NULL in the analog path.

This late NULL check is redundant, introduce a local dc_link pointer,
use it consistently, and drop the superfluous NULL check while using
dc_link->link_id.id instead.

The function uses dc_link at the very beginning without checking if it
is NULL.  But later in the code, it suddenly checks if dc_link is NULL.

This check is too late to be useful, because the code has already used
dc_link earlier.  So this NULL check does nothing.

We simplify the code by storing amdgpu_dm_connector->dc_link in a local
dc_link variable and using it throughout the function.  Since dc_link is
already dereferenced early, the later NULL check is unnecessary and is
removed.

Fixes the below:
  amdgpu_dm_connector_get_modes():
  variable dereferenced before check 'amdgpu_dm_connector->dc_link'

drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c
  8845				&amdgpu_dm_connector->dc_link->verified_link_cap;
  8846		const struct dc *dc = amdgpu_dm_connector->dc_link->dc;
                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                                      Dereference
  ...

  8856
  8857			if (amdgpu_dm_connector->dc_sink &&
  8858			    amdgpu_dm_connector->dc_link &&
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                            Checked too late.
                            Presumably this NULL check could be removed?
  ...

Fixes: d46e422f65 ("drm/amd/display: Cleanup uses of the analog flag")
Reported by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Timur Kristóf <timur.kristof@gmail.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Roman Li <roman.li@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Tom Chung <chiahsuan.chung@amd.com>
Cc: Alex Hung <alex.hung@amd.com>
Cc: Ivan Lipski <ivan.lipski@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2025-11-26 11:30:14 -05:00
arch arm64: dts: imx95: Describe Mali G310 GPU 2025-11-03 14:25:22 +00:00
block block-6.18-20251016 2025-10-17 08:31:26 -07:00
certs
crypto This push contains the following changes: 2025-10-10 08:56:16 -07:00
Documentation Merge tag 'drm-misc-next-2025-11-14-1' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-next 2025-11-17 14:21:49 +10:00
drivers drm/amd/display: Fix dereference-before-check for dc_link 2025-11-26 11:30:14 -05:00
fs Description for this pull request: 2025-10-18 07:23:59 -10:00
include Merge tag 'drm-misc-next-2025-11-14-1' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-next 2025-11-17 14:21:49 +10:00
init
io_uring io_uring/rw: check for NULL io_br_sel when putting a buffer 2025-10-15 13:38:53 -06:00
ipc
kernel drm-misc-next for v6.19: 2025-10-24 13:25:20 +02:00
lib lib/test_kho: use kho_preserve_vmalloc instead of storing addresses in fdt 2025-10-07 13:48:56 -07:00
LICENSES
mm slab: reset slab->obj_ext when freeing and it is OBJEXTS_ALLOC_FAIL 2025-10-16 15:16:45 +02:00
net bpf-fixes 2025-10-18 08:00:43 -10:00
rust rust: bitmap: fix formatting 2025-10-17 13:02:22 +02:00
samples
scripts Kbuild fixes for 6.18 #1 2025-10-11 15:47:12 -07:00
security
sound ALSA: hda/realtek: Fix mute led for HP Omen 17-cb0xxx 2025-10-17 16:37:21 +02:00
tools hid-for-linus-2025101701 2025-10-18 08:18:18 -10:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM x86 fixes for 6.18: 2025-10-18 10:25:43 +02:00
.clang-format Merge tag 'drm-misc-next-2025-10-02' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-next 2025-10-21 10:16:34 +02:00
.clippy.toml
.cocciconfig
.editorconfig
.get_maintainer.ignore
.gitattributes
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.mailmap Merge drm/drm-next into drm-misc-next 2025-10-24 14:45:08 +02:00
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MAINTAINERS amd-drm-next-6.19-2025-11-07: 2025-11-11 15:35:49 +10:00
Makefile Linux 6.18-rc2 2025-10-19 15:19:16 -10:00
README

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