GHSA-6W43-3678-PP8F
Vulnerability from github – Published: 2026-09-16 12:30 – Updated: 2026-10-30 15:33In 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.
{
"affected": [],
"aliases": [
"CVE-2026-89803"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-16T11:16:45Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/nouveau: unsubscribe the channel-kill event before the fence context\n\nnouveau_channel_del() tears the fence context down first and only drops\nthe channel-kill subscription later, in the middle of the nvif object\nteardown:\n\n\tif (chan-\u003efence)\n\t\tnouveau_fence(chan-\u003ecli-\u003edrm)-\u003econtext_del(chan);\n\t...\n\tnvif_object_dtor(\u0026chan-\u003evram);\n\tnvif_event_dtor(\u0026chan-\u003ekill);\n\nThe subscribed handler is nouveau_channel_killed(), which calls\nnouveau_channel_kill() and from there nouveau_fence_context_kill() on\nchan-\u003efence. A kill event delivered in that window takes fctx-\u003elock and\nwalks fctx-\u003epending on a fence context that context_del() has already\nfreed.\n\nNothing reaches this below Fermi today, because the subscription is\ngated on FERMI_CHANNEL_GPFIFO and nothing kills a channel there. On\nFermi and newer the window is real but narrow, since a kill has to land\nexactly while the channel is being destroyed. That is reason enough on\nits own, which is why this carries a Fixes: tag. The last patch in this\nseries subscribes Tesla channels as well; nothing kills those today, so\nit does not widen the exposure now, but it is the groundwork for a\nrecovery path that would, and the ordering is better fixed before that\nlands than alongside it.\n\nDrop the subscription before anything it depends on is torn down.",
"id": "GHSA-6w43-3678-pp8f",
"modified": "2026-10-30T15:33:27Z",
"published": "2026-09-16T12:30:36Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89803"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1fef7553dc628295c1208a4f2ac2094c62886e5d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/511585987d27d8cb668acebd399fc4deda23404c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5db663fbff7b88aeeeecaf5220e177e524165101"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ee1cfb1acdff3fe3b47de7c536e5c77443c8e74f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f3830fdd6930e233d727f29eee1617f7e6a0e9e5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f5a79a9ebfbafb87ca7a896e8d6b5f33a98d097e"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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