From 3aefc722ff52076407203b6af9713de567993adf Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Wed, 30 Mar 2022 20:04:26 +0300 Subject: [PATCH] drm/edid: fix invalid EDID extension block filtering MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The invalid EDID block filtering uses the number of valid EDID extensions instead of all EDID extensions for looping the extensions in the copy. This is fine, by coincidence, if all the invalid blocks are at the end of the EDID. However, it's completely broken if there are invalid extensions in the middle; the invalid blocks are included and valid blocks are excluded. Fix it by modifying the base block after, not before, the copy. Fixes: 14544d0937bf ("drm/edid: Only print the bad edid when aborting") Reported-by: Ville Syrjälä Signed-off-by: Jani Nikula Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20220330170426.349248-1-jani.nikula@intel.com --- drivers/gpu/drm/drm_edid.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 359c52e5318a..18e1b88cd894 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -2031,9 +2031,6 @@ struct edid *drm_do_get_edid(struct drm_connector *connector, connector_bad_edid(connector, edid, edid[0x7e] + 1); - edid[EDID_LENGTH-1] += edid[0x7e] - valid_extensions; - edid[0x7e] = valid_extensions; - new = kmalloc_array(valid_extensions + 1, EDID_LENGTH, GFP_KERNEL); if (!new) @@ -2050,6 +2047,9 @@ struct edid *drm_do_get_edid(struct drm_connector *connector, base += EDID_LENGTH; } + new[EDID_LENGTH - 1] += new[0x7e] - valid_extensions; + new[0x7e] = valid_extensions; + kfree(edid); edid = new; }