[PATCH AUTOSEL 6.11 138/244] drm/amd/display: Add NULL check for clk_mgr and clk_mgr->funcs in dcn30_init_hw

Sasha Levin
2024-09-25T11:44:59Z

From: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>

[ Upstream commit cba7fec864172dadd953daefdd26e01742b71a6a ]

This commit addresses a potential null pointer dereference issue in the
`dcn30_init_hw` function. The issue could occur when `dc->clk_mgr` or
`dc->clk_mgr->funcs` is null.

The fix adds a check to ensure `dc->clk_mgr` and `dc->clk_mgr->funcs` is
not null before accessing its functions. This prevents a potential null
pointer dereference.

Reported by smatch:
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn30/dcn30_hwseq.c:789 dcn30_init_hw() error: we previously assumed 'dc->clk_mgr' could be null (see line 628)

Cc: Tom Chung <chiahsuan.chung@amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Roman Li <roman.li@amd.com>
Cc: Alex Hung <alex.hung@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c
index eaeeade31ed74..e96019b81e03d 100644
--- a/drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c
@@ -625,7 +625,7 @@ void dcn30_init_hw(struct dc *dc)
uint32_t backlight = MAX_BACKLIGHT_LEVEL;
uint32_t user_level = MAX_BACKLIGHT_LEVEL;

- if (dc->clk_mgr && dc->clk_mgr->funcs->init_clocks)
+ if (dc->clk_mgr && dc->clk_mgr->funcs && dc->clk_mgr->funcs->init_clocks)
dc->clk_mgr->funcs->init_clocks(dc->clk_mgr);

// Initialize the dccg
@@ -786,11 +786,12 @@ void dcn30_init_hw(struct dc *dc)
if (!dcb->funcs->is_accelerated_mode(dcb) && dc->res_pool->hubbub->funcs->init_watermarks)
dc->res_pool->hubbub->funcs->init_watermarks(dc->res_pool->hubbub);

- if (dc->clk_mgr->funcs->notify_wm_ranges)
+ if (dc->clk_mgr && dc->clk_mgr->funcs && dc->clk_mgr->funcs->notify_wm_ranges)
dc->clk_mgr->funcs->notify_wm_ranges(dc->clk_mgr);

//if softmax is enabled then hardmax will be set by a different call
- if (dc->clk_mgr->funcs->set_hard_max_memclk && !dc->clk_mgr->dc_mode_softmax_enabled)
+ if (dc->clk_mgr && dc->clk_mgr->funcs && dc->clk_mgr->funcs->set_hard_max_memclk &&
+ !dc->clk_mgr->dc_mode_softmax_enabled)
dc->clk_mgr->funcs->set_hard_max_memclk(dc->clk_mgr);

if (dc->res_pool->hubbub->funcs->force_pstate_change_control)
--
2.43.0