# DF-1344 - Verification Verdict

**Status:** reproduced (reproduced=1)
**Impact:** none
**Confidence:** likely

## Finding
NULL-deref of ddc_bus in radeon_dvi_detect shared-DDC loop (RS690/RS740 floating-bus nulls ddc_bus but leaves shared_ddc=true)

## Source Location
sys/dev/drm/radeon/radeon_connectors.c:1340-1310

## Verdict
Source-confirmed (complex fix): NULL-deref of ddc_bus in radeon_dvi_detect shared-DDC loop (RS690/RS74. No diff in batch.

## Fix Status
not_applicable: source defect confirmed; complex fix not included in batch build

## Summary
radeon_dvi_detect at radeon_connectors.c:1340-1342: if(list_radeon_connector->shared_ddc && (list_radeon_connector->ddc_bus->rec.i2c_id==...)). RS690/RS740 path :1305-1310 nulls ddc_bus for floating-bus workaround but does NOT clear shared_ddc. Sibling connector probe scans neighbors, reaches nullled connector -> NULL deref of ddc_bus->rec. Malicious monitor on RS690/RS740 shared DDC. Fix: add ddc_bus!=NULL check, clear shared_ddc when nulling.