Linux Kernel NULL Pointer Dereference Vulnerability in DRM/MediaTek DP Handling

A NULL pointer dereference vulnerability has been identified in the Linux kernel's DRM/MediaTek component, specifically within the DisplayPort (DP) handling. The issue arises in the 'mtk_dp_wait_hpd_asserted()' function, which may be invoked before the 'mtk_dp->drm_dev' pointer is properly assigned. This can occur through the 'mtk_edp_wait_hpd_asserted' call, triggered during the panel probe process. The vulnerability is exploited by using 'drm' level print statements, which introduce a NULL pointer dereference. To address this, the error message in 'mtk_dp_wait_hpd_asserted()' has been changed to 'dev_err()', and similar modifications have been made to the error messages in 'mtk_dp_parse_capabilities()'.

Impact

Exploitation of this vulnerability leads to a NULL pointer dereference, causing a crash or undefined behavior in the system.