Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

drm/amd/display: Fix NULL pointer dereference in amdgpu_dm_crtc_set_vblank()

amdgpu_dm_crtc_set_vblank() dereferences acrtc_state->stream when vblank is enabled/queried from DRM_IOCTL_MODE_CRTC_GET_SEQUENCE before a stream is attached to it.

BUG: kernel NULL pointer dereference, address: 0000000000000008 RIP: amdgpu_dm_crtc_set_vblank+0x6b/0x4d0 [amdgpu] Call Trace: drm_vblank_enable drm_vblank_get drm_crtc_get_sequence_ioctl drm_ioctl_kernel drm_ioctl

Reproduced by running VKCTS with WSI tests enabled on RADV.

Guard the enable path on acrtc_state->stream being non-NULL, matching the existing checks in this function.

(cherry picked from commit 7b1b31bf6942e6f43509b48da23f8e27269aac39)