dcn42_init_hw() calls update_bw_bounding_box() when FAMS2 is disabled or when the dchub reference clock changes. However the existing condition mixes the callback pointer check with only one side of the || expression:
((!fams2_enable && update_bw_bounding_box) || freq_changed) This allows the block to be entered through the freq_changed path even when update_bw_bounding_box() is NULL. The function is then called unconditionally inside the block, which can lead to a NULL pointer dereference. Additionally, the code dereferences dc->clk_mgr->bw_params without verifying that dc->clk_mgr and bw_params are valid. Restructure the condition so that the update trigger remains the same (FAMS2 disabled or dchub ref clock changed), but guard the call with explicit checks for: - update_bw_bounding_box callback - dc->clk_mgr - dc->clk_mgr->bw_params Also introduce a helper boolean (dchub_ref_freq_changed) to improve readability of the clock-change condition. This fixes Smatch warnings about inconsistent NULL assumptions in dcn42_init_hw(). drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn42/dcn42_hwseq.c:264 dcn42_init_hw() error: we previously assumed 'dc->clk_mgr' could be null (see line 253) drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn42/dcn42_hwseq.c:278 dcn42_init_hw() error: we previously assumed 'dc->res_pool->funcs->update_bw_bounding_box' could be null (see line 274) Cc: Roman Li <[email protected]> Cc: Alex Hung <[email protected]> Cc: Jerry Zuo <[email protected]> Cc: Sun peng Li <[email protected]> Cc: Tom Chung <[email protected]> Cc: Dan Carpenter <[email protected]> Cc: Aurabindo Pillai <[email protected]> Signed-off-by: Srinivasan Shanmugam <[email protected]> --- .../amd/display/dc/hwss/dcn42/dcn42_hwseq.c | 24 +++++++++++++------ 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dcn42/dcn42_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dcn42/dcn42_hwseq.c index 8e12dc1297c4..e307cc6363dd 100644 --- a/drivers/gpu/drm/amd/display/dc/hwss/dcn42/dcn42_hwseq.c +++ b/drivers/gpu/drm/amd/display/dc/hwss/dcn42/dcn42_hwseq.c @@ -69,6 +69,7 @@ void dcn42_init_hw(struct dc *dc) int edp_num; uint32_t backlight = MAX_BACKLIGHT_LEVEL; uint32_t user_level = MAX_BACKLIGHT_LEVEL; + bool dchub_ref_freq_changed; int current_dchub_ref_freq = 0; if (dc->clk_mgr && dc->clk_mgr->funcs && dc->clk_mgr->funcs->init_clocks) { @@ -260,8 +261,12 @@ void dcn42_init_hw(struct dc *dc) if (dc->res_pool->hubbub->funcs->init_crb) dc->res_pool->hubbub->funcs->init_crb(dc->res_pool->hubbub); - if (dc->res_pool->hubbub->funcs->set_request_limit && dc->config.sdpif_request_limit_words_per_umc > 0) - dc->res_pool->hubbub->funcs->set_request_limit(dc->res_pool->hubbub, dc->clk_mgr->bw_params->num_channels, dc->config.sdpif_request_limit_words_per_umc); + if (dc->res_pool->hubbub->funcs->set_request_limit && + dc->clk_mgr && dc->clk_mgr->bw_params && + dc->config.sdpif_request_limit_words_per_umc > 0) + dc->res_pool->hubbub->funcs->set_request_limit(dc->res_pool->hubbub, + dc->clk_mgr->bw_params->num_channels, + dc->config.sdpif_request_limit_words_per_umc); // Get DMCUB capabilities if (dc->ctx->dmub_srv) { @@ -269,13 +274,18 @@ void dcn42_init_hw(struct dc *dc) dc->caps.dmub_caps.psr = dc->ctx->dmub_srv->dmub->feature_caps.psr; dc->caps.dmub_caps.mclk_sw = dc->ctx->dmub_srv->dmub->feature_caps.fw_assisted_mclk_switch_ver > 0; dc->caps.dmub_caps.fams_ver = dc->ctx->dmub_srv->dmub->feature_caps.fw_assisted_mclk_switch_ver; + + /* sw and fw FAMS versions must match for support */ dc->debug.fams2_config.bits.enable &= - dc->caps.dmub_caps.fams_ver == dc->debug.fams_version.ver; // sw & fw fams versions must match for support - if ((!dc->debug.fams2_config.bits.enable && dc->res_pool->funcs->update_bw_bounding_box) - || res_pool->ref_clocks.dchub_ref_clock_inKhz / 1000 != current_dchub_ref_freq) { + dc->caps.dmub_caps.fams_ver == dc->debug.fams_version.ver; + dchub_ref_freq_changed = + res_pool->ref_clocks.dchub_ref_clock_inKhz / 1000 != current_dchub_ref_freq; + + if ((!dc->debug.fams2_config.bits.enable || dchub_ref_freq_changed) && + dc->res_pool->funcs->update_bw_bounding_box && + dc->clk_mgr && dc->clk_mgr->bw_params) { /* update bounding box if FAMS2 disabled, or if dchub clk has changed */ - if (dc->clk_mgr) - dc->res_pool->funcs->update_bw_bounding_box(dc, dc->clk_mgr->bw_params); + dc->res_pool->funcs->update_bw_bounding_box(dc, dc->clk_mgr->bw_params); } } if (dc->res_pool->pg_cntl) { -- 2.34.1
