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medium4.7

CVE-2024-26874

In the Linux kernel, the following vulnerability has been resolved: drm/mediatek: Fix a null pointer crash in mtk_drm_crtc_finish_page_flip It's possible that …

Impact

In the Linux kernel, the following vulnerability has been resolved: drm/mediatek: Fix a null pointer crash in mtk_drm_crtc_finish_page_flip It's possible that mtk_crtc->event is NULL in mtk_drm_crtc_finish_page_flip(). pending_needs_vblank value is set by mtk_crtc->event, but in mtk_drm_crtc_atomic_flush(), it's is not guarded by the same lock in mtk_drm_finish_page_flip(), thus a race condition happens. Consider the following case: CPU1 CPU2 step 1: mtk_drm_crtc_atomic_begin() mtk_crtc->event is not null, step 1: mtk_drm_crtc_atomic_flush: mtk_drm_crtc_update_config( !!mtk_crtc->event) step 2: mtk_crtc_ddp_irq -> mtk_drm_finish_page_flip: lock mtk_crtc->event set to null, pending_needs_vblank set to false unlock pending_needs_vblank set to true, step 2: mtk_crtc_ddp_irq -> mtk_drm_finish_page_flip called again, pending_needs_vblank is still true //null pointer Instead of guarding the entire mtk_drm_crtc_atomic_flush(), it's more efficient to just check if mtk_crtc->event is null before use.

Affected products

VendorProductAffected versions
LinuxLinux Kernel
from 4.7 before 4.19.311
from 4.20 before 5.4.273
from 5.5 before 5.10.214
from 5.11 before 5.15.153
from 5.16 before 6.1.83
from 6.2 before 6.6.23
DebianDebian Linux
Version 10.0

Weakness classification

CWE-476

References