linux-kernel - [PATCH AUTOSEL 6.0 13/44] drm/amd/display: Fix variable dereferenced before check

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Date:   Sun,  9 Oct 2022 19:49:01 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     sunliming <sunliming@...inos.cn>,
        kernel test robot <lkp@...el.com>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        Alex Deucher <alexander.deucher@....com>,
        Sasha Levin <sashal@...nel.org>, harry.wentland@....com,
        sunpeng.li@....com, Rodrigo.Siqueira@....com,
        christian.koenig@....com, Xinhui.Pan@....com, airlied@...il.com,
        daniel@...ll.ch, Alvin.Lee2@....com, Jun.Lei@....com,
        Brian.Chang@....com, felipe.clark@....com,
        aurabindo.pillai@....com, amd-gfx@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 6.0 13/44] drm/amd/display: Fix variable dereferenced before check

From: sunliming <sunliming@...inos.cn>

[ Upstream commit 45a92f45f4578ff89da7dc5ef50bab4ef870f3b7 ]

Fixes the following smatch warning:

drivers/gpu/drm/amd/amdgpu/../display/dc/dc_dmub_srv.c:311 dc_dmub_srv_p_state_delegate()
warn: variable dereferenced before check 'dc' (see line 309)

Reported-by: kernel test robot <lkp@...el.com>
Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: sunliming <sunliming@...inos.cn>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
index 52a61b3e5a8b..2e243b70747f 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
+++ b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
@@ -323,11 +323,13 @@ bool dc_dmub_srv_p_state_delegate(struct dc *dc, bool should_manage_pstate, stru
 	struct dmub_cmd_fw_assisted_mclk_switch_config *config_data = &cmd.fw_assisted_mclk_switch.config_data;
 	int i = 0;
 	int ramp_up_num_steps = 1; // TODO: Ramp is currently disabled. Reenable it.
-	uint8_t visual_confirm_enabled = dc->debug.visual_confirm == VISUAL_CONFIRM_FAMS;
+	uint8_t visual_confirm_enabled;
 
 	if (dc == NULL)
 		return false;
 
+	visual_confirm_enabled = dc->debug.visual_confirm == VISUAL_CONFIRM_FAMS;
+
 	// Format command.
 	cmd.fw_assisted_mclk_switch.header.type = DMUB_CMD__FW_ASSISTED_MCLK_SWITCH;
 	cmd.fw_assisted_mclk_switch.header.sub_type = DMUB_CMD__FAMS_SETUP_FW_CTRL;
-- 
2.35.1