linux-kernel - [PATCH] drm/i915/display: Avoid nonliteral printf format string

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Message-Id: <20251204094401.1029917-1-arnd@kernel.org>
Date: Thu,  4 Dec 2025 10:43:51 +0100
From: Arnd Bergmann <arnd@...nel.org>
To: Jani Nikula <jani.nikula@...ux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@...el.com>,
	Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
	Tvrtko Ursulin <tursulin@...ulin.net>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Mika Kahola <mika.kahola@...el.com>
Cc: Arnd Bergmann <arnd@...db.de>,
	Ville Syrjälä <ville.syrjala@...ux.intel.com>,
	Ankit Nautiyal <ankit.k.nautiyal@...el.com>,
	Suraj Kandpal <suraj.kandpal@...el.com>,
	Jouni Högander <jouni.hogander@...el.com>,
	intel-gfx@...ts.freedesktop.org,
	intel-xe@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] drm/i915/display: Avoid nonliteral printf format string

From: Arnd Bergmann <arnd@...db.de>

pipe_config_mismatch() takes a printf-style format string and arguments,
not a constant string, so this trigers -Wformat warnings when they are
not disabled:

drivers/gpu/drm/i915/display/intel_display.c: In function 'pipe_config_cx0pll_mismatch':
drivers/gpu/drm/i915/display/intel_display.c:4997:9: error: format not a string literal and no format arguments [-Werror=format-security]
 4997 |         pipe_config_mismatch(p, fastset, crtc, name, chipname);
      |         ^~~~~~~~~~~~~~~~~~~~

drivers/gpu/drm/i915/display/intel_display.c: In function 'pipe_config_lt_phy_pll_mismatch':
drivers/gpu/drm/i915/display/intel_display.c:5027:9: error: format not a string literal and no format arguments [-Werror=format-security]
 5027 |         pipe_config_mismatch(p, fastset, crtc, name, chipname);
      |         ^~~~~~~~~~~~~~~~~~~~

Use either the string literal or the trivial "%s" format so the compiler can
prove this to be used correctly.

Fixes: 45fe957ae769 ("drm/i915/display: Add compare config for MTL+ platforms")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/gpu/drm/i915/display/intel_display.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 7b4fd18c60e2..83025d5a4aa9 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -4987,7 +4987,7 @@ pipe_config_cx0pll_mismatch(struct drm_printer *p, bool fastset,
 	struct intel_display *display = to_intel_display(crtc);
 	char *chipname = a->use_c10 ? "C10" : "C20";
 
-	pipe_config_mismatch(p, fastset, crtc, name, chipname);
+	pipe_config_mismatch(p, fastset, crtc, name, "%s", chipname);
 
 	drm_printf(p, "expected:\n");
 	intel_cx0pll_dump_hw_state(display, a);
@@ -5022,9 +5022,8 @@ pipe_config_lt_phy_pll_mismatch(struct drm_printer *p, bool fastset,
 				const struct intel_lt_phy_pll_state *b)
 {
 	struct intel_display *display = to_intel_display(crtc);
-	char *chipname = "LTPHY";
 
-	pipe_config_mismatch(p, fastset, crtc, name, chipname);
+	pipe_config_mismatch(p, fastset, crtc, name, "LTPHY");
 
 	drm_printf(p, "expected:\n");
 	intel_lt_phy_dump_hw_state(display, a);
-- 
2.39.5