drm/client: Fully protect modes[] with dev->mode_config.mutex

commit 3eadd887dbac1df8f25f701e5d404d1b90fd0fea upstream.

The modes[] array contains pointers to modes on the connectors'
mode lists, which are protected by dev->mode_config.mutex.
Thus we need to extend modes[] the same protection or by the
time we use it the elements may already be pointing to
freed/reused memory.

Cc: stable@vger.kernel.org
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/10583
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240404203336.10454-2-ville.syrjala@linux.intel.com
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
index 871e4e2129d6daac8dadcb3262227451c59296c8..0683a129b36285cc96c25d57d3115cb111fc2003 100644 (file)
--- a/drivers/gpu/drm/drm_client_modeset.c
+++ b/drivers/gpu/drm/drm_client_modeset.c
@@ -777,6 +777,7 @@ int drm_client_modeset_probe(struct drm_client_dev *client, unsigned int width,
        unsigned int total_modes_count = 0;
        struct drm_client_offset *offsets;
        unsigned int connector_count = 0;
+       /* points to modes protected by mode_config.mutex */
        struct drm_display_mode **modes;
        struct drm_crtc **crtcs;
        int i, ret = 0;
@@ -845,7 +846,6 @@ int drm_client_modeset_probe(struct drm_client_dev *client, unsigned int width,
                drm_client_pick_crtcs(client, connectors, connector_count,
                                      crtcs, modes, 0, width, height);
        }
-       mutex_unlock(&dev->mode_config.mutex);
 
        drm_client_modeset_release(client);
 
@@ -875,6 +875,7 @@ int drm_client_modeset_probe(struct drm_client_dev *client, unsigned int width,
                        modeset->y = offset->y;
                }
        }
+       mutex_unlock(&dev->mode_config.mutex);
 
        mutex_unlock(&client->modeset_mutex);
 out: