CVE-2026-98786

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

drm/amd/display: guard dc_sink dereferences in MST mode validation

dm_dp_mst_is_port_support_mode() reads aconnector->dc_sink->dsc_caps… for the DSC branch-throughput check, and get_conv_frl_bw()s HDMI-PCON FRL-bandwidth path reads aconnector->dc_sink->edid_caps.max_frl_rate, both without a NULL check. dc_sink is cleared asynchronously on MST unplug, and both functions run from paths that the drivers own comments document as racing that teardown: the connector probe workers ->mode_valid callback and a compositors atomic check, neither of which holds the MST manager lock that the teardown path uses. The former does have an existing dsc_aux NULL check, but dsc_aux isnt reliably cleared in every path that clears dc_sink, so it doesnt cover this.

Fail the port-support check and skip the FRL conversion path when the sink is already gone.

(cherry picked from commit 7c3db8da4e039698ae198c870712428644e965c7)

Affected Software

References

• https://git.kernel.org/stable/c/217f64f348c90cba62164e7ff38e0ccf78a5ca09
• https://git.kernel.org/stable/c/daa0437fe5e451856aaf8fda602a9fc2105bbd54