# DF-2014 - Source Verification

## Verdict: REPRODUCED (source-only confirmation)

**Finding**: sys/dev/drm/radeon/radeon_gart.c:254-265

**Mechanism**: radeon_gart_unbind outer loop always increments CPU-page index p. Inner GPU-page index t only advances inside if(pages[p]) guard. NULL page → t desyncs from p → stale DMA mappings left behind.

**Hardware dependency**: Requires radeon GPU with GART.

**Fix**: Always advance t by PAGE_SIZE/GPU_PAGE_SIZE in outer loop, regardless of pages[p] NULL.

## Verification method
Source-only confirmation. The cited code path was traced line-by-line in the
audited sys/ tree. The bug exists exactly as described. This is a HW-gated
driver finding — the vulnerable code path requires specific hardware (GPU,
controller, PHY, TPM, etc.) not present in the QEMU audit guest. Runtime
reproduction on this guest is not possible without the hardware.

## Fix validation
fix.diff authored and applied to guest source. All 40 fixes in this batch
compile cleanly in a single combined kernel build: `make -j6 nativekernel
KERNCONF=X86_64_GENERIC` → rc=0, zero -Werror violations.

**Kernel**: DragonFly 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026