[PATCH 6.6 093/122] drm/client: Fully protect modes[] with dev->mode_config.mutex

Greg Kroah-Hartman
2024-04-15T14:36:46Z

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

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>
---
drivers/gpu/drm/drm_client_modeset.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- 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_
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_
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_
modeset->y = offset->y;
}
}
+ mutex_unlock(&dev->mode_config.mutex);

mutex_unlock(&client->modeset_mutex);