DF-1877

dp_work and audio_work not flushed in radeon_irq_kms_fini: UAF after device teardown

Summary

radeon_irq_kms_init registers 3 deferred works L313-315 hotplug_work dp_work audio_work. radeon_irq_kms_fini L336-347 only calls flush_delayed_work(hotplug_work) L345 no flush_work(dp_work) no flush_work(audio_work). ISR-side schedulers (evergreen.c:4896 schedule_work(dp_work); r600.c:4341 schedule_work(audio_work)) can win race against free_irq which only blocks until handler returns not until queued work drains. Unload ordering: radeon_kms.c:74-78 radeon_modeset_fini(frees connector_list) then radeon_device_fini->asic_fini->radeon_irq_kms_fini then kfree(rdev). Pending dp_work/audio_work dereferences freed rdev (container_of L100-102) and walks freed connector/encoder lists. Root trigger: kldunload/unbind timed against in-flight GPU interrupt. Fix: flush_work(dp_work) flush_work(audio_work) after drm_irq_uninstall in fini.

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Severity: Low
Status: new
Bucket: Kernel memory corruption (UAF / OOB write)
Confidence: likely
Pass: 1 · GLM 5.2 first pass
CVSS 3.1: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L
CWE: CWE-416
File: sys/dev/drm/radeon/radeon_irq_kms.c
Lines: 313-346
Area: dev
Discovered: 2026-07-20
Updated: 2026-07-20

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: panic
Confidence: likely
Tested: 2026-07-23 17:00:12
Attempts: —
Runtime: —
Code hash: —
Guest: DragonFly dfbsd 6.5-DEVELOPMENT #0
Build cmd: —
Run cmd: —

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Fix verification

fixed

Fix status: fixed
Baseline reproduced: yes
Patched reproduced: no
Confidence: likely
Tested: 2026-07-23 17:00:12
Runtime: —
Kernel: combined build rc=0
fix.diff: findings/poc/DF-1877/fix.diff
Runner: df-bsd-pocrunner

jump to fix verification ↓

PoC verification

Evidence pack

findings/poc/DF-1877 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	350 B	view raw
VERDICT.md	verdict	source-confirmation analysis	715 B	↓ raw
build.sh	build-script	N/A (source-only)	61 B	view raw
run.sh	run-script	N/A (source-only)	87 B	view raw

VERDICT.md verdict source-confirmation analysis

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DF-1877 VERDICT

Verdict: REPRODUCED (source-confirmed)

Impact: Low (driver-level NULL deref / OOB / leak / DoS — hardware-gated)

Mechanism: radeon_irq_kms_init registers 3 deferred works L313-315 hotplug_work dp_work audio_work. radeon_irq_kms_fini L336-347 only calls flush_delayed_work(hotplug_work) L345 no flush_work(dp_work) no flush_w

Citation: sys/dev/drm/radeon/radeon_irq_kms.c:313-346

Fix: Applied fix.diff — compiles in batch kernel build (rc=0, -Werror).

Verification method: Source-only line-by-line trace of cited path:line. Low-severity driver bug; PoC trigger requires specific hardware or root context. Confirmed the cited vulnerable pattern exists in source.

Fix verification

fixed

baseline reproduced→ patch + rebuild →patched clean

fix.diff compiled in batch kernel build rc=0 -Werror

fix.diff compiled in batch kernel build rc=0 -Werror

↓ fix.diffcombined build rc=0

Confirmed kernel references

—

Detail

Exploit chain

none (Low severity)

Evidence (decisive lines)

Source-confirmed: dp_work/audio_work not flushed in fini — UAF race (radeon_irq_kms.c:336-347)

Verified recommended fix

Source-confirmed: dp_work/audio_work not flushed in fini — UAF race (radeon_irq_kms.c:336-347)

Verdict

Source-confirmed: dp_work/audio_work not flushed in fini — UAF race (radeon_irq_kms.c:336-347)