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[72.110.123.76]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-c741e546b01sm334350a12.21.2026.03.17.12.16.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Mar 2026 12:16:27 -0700 (PDT) From: Gui-Dong Han To: gregkh@linuxfoundation.org, dakr@kernel.org, rafael@kernel.org, jani.nikula@linux.intel.com, rodrigo.vivi@intel.com, joonas.lahtinen@linux.intel.com, tursulin@ursulin.net, airlied@gmail.com, simona@ffwll.ch Cc: gustavo.sousa@intel.com, demarchi@kernel.org, jouni.hogander@intel.com, luciano.coelho@intel.com, linux-kernel@vger.kernel.org, driver-core@lists.linux.dev, intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-sound@vger.kernel.org, akaieurus@gmail.com, me@ziyao.cc, Gui-Dong Han Subject: [PATCH 4/4] drm/i915/display: initialize string params to empty strings Date: Wed, 18 Mar 2026 03:15:38 +0800 Message-ID: <20260317191538.43535-1-hanguidong02@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260317185920.43387-1-hanguidong02@gmail.com> References: <20260317185920.43387-1-hanguidong02@gmail.com> Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Passing NULL to debugfs_create_str() causes a NULL pointer dereference upon reading, and is no longer permitted. Change the default values of dmc_firmware_path and vbt_firmware to empty strings (""). Existing code that consumes these parameters already verifies both pointer validity and string length, so empty strings are handled correctly. Furthermore, heap allocation is not required here: these debugfs parameters are created with strictly read-only permissions (0400). As a result, the debugfs write operation is never invoked, meaning the static empty string will not be erroneously freed by kfree(). Fixes: e9913f0bd2e1 ("drm/i915/display: move dmc_firmware_path to display params") Fixes: 29292bc6cc37 ("drm/i915/display: Move vbt_firmware module parameter under display") Signed-off-by: Gui-Dong Han --- drivers/gpu/drm/i915/display/intel_display_params.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_display_params.h b/drivers/gpu/drm/i915/display/intel_display_params.h index b95ecf728daa..0a8cad98d480 100644 --- a/drivers/gpu/drm/i915/display/intel_display_params.h +++ b/drivers/gpu/drm/i915/display/intel_display_params.h @@ -23,8 +23,8 @@ struct drm_printer; * debugfs file */ #define INTEL_DISPLAY_PARAMS_FOR_EACH(param) \ - param(char *, dmc_firmware_path, NULL, 0400) \ - param(char *, vbt_firmware, NULL, 0400) \ + param(char *, dmc_firmware_path, "", 0400) \ + param(char *, vbt_firmware, "", 0400) \ param(int, lvds_channel_mode, 0, 0400) \ param(int, panel_use_ssc, -1, 0600) \ param(int, vbt_sdvo_panel_type, -1, 0400) \ -- 2.43.0