Patch "drm/amd/display: Add NULL check for clk_mgr and clk_mgr->funcs in dcn401_init_hw" has been added to the 6.11-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/amd/display: Add NULL check for clk_mgr and clk_mgr->funcs in dcn401_init_hw

to the 6.11-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-amd-display-add-null-check-for-clk_mgr-and-clk_m.patch
and it can be found in the queue-6.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit b204c3ee8c5a17bac98bb5d544e88d22e3cf263f
Author: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
Date:   Mon Jul 22 16:58:32 2024 +0530

    drm/amd/display: Add NULL check for clk_mgr and clk_mgr->funcs in dcn401_init_hw
    
    [ Upstream commit 4b6377f0e96085cbec96eb7f0b282430ccdd3d75 ]
    
    This commit addresses a potential null pointer dereference issue in the
    `dcn401_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/dcn401/dcn401_hwseq.c:416 dcn401_init_hw() error: we previously assumed 'dc->clk_mgr' could be null (see line 225)
    
    Cc: Tom Chung <chiahsuan.chung@xxxxxxx>
    Cc: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx>
    Cc: Roman Li <roman.li@xxxxxxx>
    Cc: Alex Hung <alex.hung@xxxxxxx>
    Cc: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
    Cc: Harry Wentland <harry.wentland@xxxxxxx>
    Cc: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
    Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
    Reviewed-by: Alex Hung <alex.hung@xxxxxxx>
    Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c
index 2c50c0f745a0b..324e77ceaf1cf 100644
--- a/drivers/gpu/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c
@@ -222,7 +222,7 @@ void dcn401_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);
 
 		// mark dcmode limits present if any clock has distinct AC and DC values from SMU
@@ -413,7 +413,7 @@ void dcn401_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 (dc->clk_mgr->funcs->set_hard_max_memclk && !dc->clk_mgr->dc_mode_softmax_enabled)
@@ -438,7 +438,9 @@ void dcn401_init_hw(struct dc *dc)
 		dc->debug.fams2_config.bits.enable &= dc->ctx->dmub_srv->dmub->feature_caps.fw_assisted_mclk_switch_ver == 2;
 		if (!dc->debug.fams2_config.bits.enable && dc->res_pool->funcs->update_bw_bounding_box) {
 			/* update bounding box if FAMS2 disabled */
-			dc->res_pool->funcs->update_bw_bounding_box(dc, dc->clk_mgr->bw_params);
+			if (dc->clk_mgr)
+				dc->res_pool->funcs->update_bw_bounding_box(dc,
+									    dc->clk_mgr->bw_params);
 		}
 	}
 }