6.8-stable review patch. If anyone has any objections, please let me know.
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From: Jani Nikula jani.nikula@intel.com
[ Upstream commit 7af03e688792293ba33149fb8df619a8dff90e80 ]
The .get_modes() callback is supposed to return the number of modes, never a negative error code. If a negative value is returned, it'll just be interpreted as a negative count, and added to previous calculations.
Document the rules, but handle the negative values gracefully with an error message.
Cc: stable@vger.kernel.org Acked-by: Thomas Zimmermann tzimmermann@suse.de Link: https://patchwork.freedesktop.org/patch/msgid/50208c866facc33226a3c77b82bb96... Signed-off-by: Jani Nikula jani.nikula@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/drm_probe_helper.c | 7 +++++++ include/drm/drm_modeset_helper_vtables.h | 3 ++- 2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c index 23b4e9a3361d8..744cde9db246b 100644 --- a/drivers/gpu/drm/drm_probe_helper.c +++ b/drivers/gpu/drm/drm_probe_helper.c @@ -419,6 +419,13 @@ static int drm_helper_probe_get_modes(struct drm_connector *connector)
count = connector_funcs->get_modes(connector);
+ /* The .get_modes() callback should not return negative values. */ + if (count < 0) { + drm_err(connector->dev, ".get_modes() returned %pe\n", + ERR_PTR(count)); + count = 0; + } + /* * Fallback for when DDC probe failed in drm_get_edid() and thus skipped * override/firmware EDID. diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h index 881b03e4dc288..9ed42469540eb 100644 --- a/include/drm/drm_modeset_helper_vtables.h +++ b/include/drm/drm_modeset_helper_vtables.h @@ -898,7 +898,8 @@ struct drm_connector_helper_funcs { * * RETURNS: * - * The number of modes added by calling drm_mode_probed_add(). + * The number of modes added by calling drm_mode_probed_add(). Return 0 + * on failures (no modes) instead of negative error codes. */ int (*get_modes)(struct drm_connector *connector);