DF-1910

i2s_pdata never freed: per-attach memory leak in all error paths of acp_hw_init

Summary

i2s_pdata kcalloc L242 (3*sizeof i2s_platform_data) passed by pointer to acp_cell[1..3].platform_data L325/331/337 consumed (copied) by mfd_add_hotplug_devices L340. No kfree(i2s_pdata) on success return L394; none on error returns L343/350/369/386; none in acp_hw_fini L462-464 (frees only acp_res/acp_genpd/acp_cell). Same error paths also leak pm_genpd_initd acp_genpd (no pm_genpd_remove see DF-1909) and partially-registered mfd cells. Every attach cycle leaks >=3*sizeof(i2s_platform_data); failed attach leaks full set. Root trigger kldload/kldunload loop or PCI rebind. Low-rate local DoS by memory exhaustion. Fix: kfree(i2s_pdata) after mfd_add copies + unified err: label.

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Severity: Low
Status: new
Bucket: Kernel memory leaks / uninitialized disclosure
Confidence: certain
Pass: 1 · GLM 5.2 first pass
CVSS 3.1: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U:C:N/I:N/A:L
CWE: CWE-401
File: sys/dev/drm/amd/amdgpu/amdgpu_acp.c
Lines: 242-464
Area: dev
Discovered: 2026-07-20
Updated: 2026-07-20

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: leak
Confidence: certain
Tested: 2026-07-23 17:00:15
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: certain
Tested: 2026-07-23 17:00:15
Runtime: —
Kernel: combined build rc=0
fix.diff: findings/poc/DF-1910/fix.diff
Runner: df-bsd-pocrunner

jump to fix verification ↓

PoC verification

Evidence pack

findings/poc/DF-1910 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	854 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

↓ download raw

DF-1910 VERDICT

Verdict: REPRODUCED (source-confirmed)

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

Mechanism: i2s_pdata kcalloc L242 (3*sizeof i2s_platform_data) passed by pointer to acp_cell[1..3].platform_data L325/331/337 consumed (copied) by mfd_add_hotplug_devices L340. No kfree(i2s_pdata) on success ret

Citation: sys/dev/drm/amd/amdgpu/amdgpu_acp.c:242-464

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: i2s_pdata kcalloc never freed in any path (amdgpu_acp.c:242-464)

Verified recommended fix

Source-confirmed: i2s_pdata kcalloc never freed in any path (amdgpu_acp.c:242-464)

Verdict

Source-confirmed: i2s_pdata kcalloc never freed in any path (amdgpu_acp.c:242-464)