# PoC DF-1587: vega10_processpptables NULL deref vdd_dep_on_sclk missing (sibling of DF-1575)

**Class:** NULL pointer deref
**Cited site:** `sys/dev/drm/amd/powerplay/hwmgr/vega10_processpptables.c:781,907,931-934,964-967`

## Reproduction status

HW/module gated — **cannot be live-triggered on the audit QEMU guest.**

The audit guest has only virtio + PIIX3 PCI devices (`pciconf -lv` shows no
AMD/Intel GPU, no ath NIC, no AdvanSys SCSI, no mfi/tws/mrsas RAID, etc.),
so the cited code path is not reachable at runtime on this guest.

The bug is **confirmed at the source level** by tracing the cited path:line
in `sys/dev/drm/amd/powerplay/hwmgr/vega10_processpptables.c` and confirming the vulnerable code is
present in the master DEV kernel tree. The `fix.diff` in this folder is
validated to apply cleanly and compile under `-Werror` (see `VERDICT.md`).

## Mechanism

vega10_processpptables.c:781 pcie_count = table_info->vdd_dep_on_sclk->count unconditionally. vdd_dep_on_sclk NULL when usGfxclkDependencyTableOffset==0 (907 init, only populated 931-934 when offset!=0). PCIE path gated only on usPCIETableOffset (964-967). VBIOS with usPCIETableOffset!=0 + usGfxclkDependencyTableOffset==0 -> NULL deref panic.

## Realistic impact ceiling (on suitable HW)

deterministic NULL deref panic via crafted VBIOS

## Fix

NULL-guard table_info->vdd_dep_on_sclk at the top of get_pcie_table; kfree the allocated pcie_table and return -EINVAL.

See `fix.diff` for the git-apply-able patch.

## How to validate the fix

```sh
scp -F dfbsd-qemu/config fix.diff dfbsd:/root/DF-1587.diff
ssh -F dfbsd-qemu/config dfbsd 'cd /usr/src && patch -p1 --forward < /root/DF-1587.diff'
ssh -F dfbsd-qemu/config dfbsd 'cd /usr/src && make -j6 nativekernel KERNCONF=X86_64_GENERIC'
# rc=0 expected; see fix_apply.log + fix_build.log in this folder.
```