---
id: CVE-2026-89803
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  drm/nouveau: unsubscribe the channel-kill event before the fence context

  nouveau_channel_del() tears the fence context down first and only drops
  the channel-kill subsc…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  drm/nouveau: unsubscribe the channel-kill event before the fence context

  nouveau_channel_del() tears the fence context down first and only drops
  the channel-kill subsc…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ea13e5abf807ea912ce84eef6a1946b9a38c6508 <
    f5a79a9ebfbafb87ca7a896e8d6b5f33a98d097e
  - >-
    Linux >= ea13e5abf807ea912ce84eef6a1946b9a38c6508 <
    f3830fdd6930e233d727f29eee1617f7e6a0e9e5
  - >-
    Linux >= ea13e5abf807ea912ce84eef6a1946b9a38c6508 <
    1fef7553dc628295c1208a4f2ac2094c62886e5d
  - >-
    Linux >= ea13e5abf807ea912ce84eef6a1946b9a38c6508 <
    511585987d27d8cb668acebd399fc4deda23404c
  - Linux 5.6
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T15:18:09.993'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89803'
references:
  - url: 'https://git.kernel.org/stable/c/1fef7553dc628295c1208a4f2ac2094c62886e5d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/511585987d27d8cb668acebd399fc4deda23404c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f3830fdd6930e233d727f29eee1617f7e6a0e9e5'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f5a79a9ebfbafb87ca7a896e8d6b5f33a98d097e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-16T10:53:54.008Z'
epss: 0.00163
epssPercentile: 0.05939
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

drm/nouveau: unsubscribe the channel-kill event before the fence context

nouveau_channel_del() tears the fence context down first and only drops
the channel-kill subscription later, in the middle of the nvif object
teardown:

	if (chan->fence)
		nouveau_fence(chan->cli->drm)->context_del(chan);
	...
	nvif_object_dtor(&chan->vram);
	nvif_event_dtor(&chan->kill);

The subscribed handler is nouveau_channel_killed(), which calls
nouveau_channel_kill() and from there nouveau_fence_context_kill() on
chan->fence. A kill event delivered in that window takes fctx->lock and
walks fctx->pending on a fence context that context_del() has already
freed.

Nothing reaches this below Fermi today, because the subscription is
gated on FERMI_CHANNEL_GPFIFO and nothing kills a channel there. On
Fermi and newer the window is real but narrow, since a kill has to land
exactly while the channel is being destroyed. That is reason enough on
its own, which is why this carries a Fixes: tag. The last patch in this
series subscribes Tesla channels as well; nothing kills those today, so
it does not widen the exposure now, but it is the groundwork for a
recovery path that would, and the ordering is better fixed before that
lands than alongside it.

Drop the subscription before anything it depends on is torn down.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.