GHSA-Q92C-JH6H-6XRQ

Vulnerability from github – Published: 2026-09-04 18:31 – Updated: 2026-09-04 18:31
VLAI
Details

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

iommu/tegra241-cmdqv: Fix CMD_SYNC use-after-free on teardown

arm_smmu_impl_remove() is registered as a devres action in arm_smmu_impl_probe(), before arm_smmu_init_queues() allocates smmu->cmdq.q.base. On a devres unwind, whether a failed probe or an unbind, the queue is freed first and arm_smmu_impl_remove() then runs tegra241_cmdqv_remove_vintf(), whose VINTF deinit issues a CMD_SYNC on the freed memory.

Observed during testing with a QEMU hack that makes the VCMDQ fail to enable, so the impl reset fails and probe aborts into the devres unwind:

platform NVDA200C:00: tegra241_cmdqv: VINTF0: VCMDQ0/LVCMDQ0: failed to enable, STATUS=0x00000000 platform NVDA200C:00: tegra241_cmdqv: VINTF0: VCMDQ0/LVCMDQ0: GERRORN=0x0, GERROR=0x4, CONS=0x0 platform NVDA200C:00: tegra241_cmdqv: VINTF0: VCMDQ0/LVCMDQ0: uncleared error detected, resetting arm-smmu-v3 arm-smmu-v3.0.auto: failed to reset impl arm-smmu-v3 arm-smmu-v3.0.auto: probe with driver arm-smmu-v3 failed with error -110 Unable to handle kernel paging request at virtual address ffff8000891e0098 ... Internal error: Oops: 0000000096000047 [#1] SMP ... Call trace: arm_smmu_cmdq_issue_cmdlist+0x320/0x6fc (P) tegra241_vcmdq_hw_deinit+0x98/0x168 tegra241_vintf_hw_deinit+0x5c/0x1b0 tegra241_cmdqv_remove_vintf+0x34/0xec tegra241_cmdqv_remove+0x40/0x9c arm_smmu_impl_remove+0x20/0x30 devm_action_release+0x14/0x20 devres_release_all+0xa8/0x110 device_unbind_cleanup+0x18/0x84 really_probe+0x1f0/0x29c

Drop the VINTF deinit from tegra241_cmdqv_remove_vintf() so the unwind no longer touches the freed queue. Quiesce the VINTFs earlier instead. Add a device_disable() impl op and run it from arm_smmu_disable_action() while the CMDQ is still up. That handles a live unbind. A failed reset is already handled because tegra241_vintf_hw_init() deinits the VINTF on its own error path. tegra241_cmdqv_remove_vintf() is also used by the iommufd viommu destroy path, so quiesce there too.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80818"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-04T16:18:09Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/tegra241-cmdqv: Fix CMD_SYNC use-after-free on teardown\n\narm_smmu_impl_remove() is registered as a devres action in\narm_smmu_impl_probe(), before arm_smmu_init_queues() allocates\nsmmu-\u003ecmdq.q.base. On a devres unwind, whether a failed probe or an\nunbind, the queue is freed first and arm_smmu_impl_remove() then runs\ntegra241_cmdqv_remove_vintf(), whose VINTF deinit issues a CMD_SYNC on\nthe freed memory.\n\nObserved during testing with a QEMU hack that makes the VCMDQ fail to\nenable, so the impl reset fails and probe aborts into the devres unwind:\n\n platform NVDA200C:00: tegra241_cmdqv: VINTF0: VCMDQ0/LVCMDQ0: failed to enable, STATUS=0x00000000\n platform NVDA200C:00: tegra241_cmdqv: VINTF0: VCMDQ0/LVCMDQ0: GERRORN=0x0, GERROR=0x4, CONS=0x0\n platform NVDA200C:00: tegra241_cmdqv: VINTF0: VCMDQ0/LVCMDQ0: uncleared error detected, resetting\n arm-smmu-v3 arm-smmu-v3.0.auto: failed to reset impl\n arm-smmu-v3 arm-smmu-v3.0.auto: probe with driver arm-smmu-v3 failed with error -110\n Unable to handle kernel paging request at virtual address ffff8000891e0098\n ...\n Internal error: Oops: 0000000096000047 [#1] SMP\n ...\n Call trace:\n  arm_smmu_cmdq_issue_cmdlist+0x320/0x6fc (P)\n  tegra241_vcmdq_hw_deinit+0x98/0x168\n  tegra241_vintf_hw_deinit+0x5c/0x1b0\n  tegra241_cmdqv_remove_vintf+0x34/0xec\n  tegra241_cmdqv_remove+0x40/0x9c\n  arm_smmu_impl_remove+0x20/0x30\n  devm_action_release+0x14/0x20\n  devres_release_all+0xa8/0x110\n  device_unbind_cleanup+0x18/0x84\n  really_probe+0x1f0/0x29c\n\nDrop the VINTF deinit from tegra241_cmdqv_remove_vintf() so the unwind no\nlonger touches the freed queue. Quiesce the VINTFs earlier instead. Add a\ndevice_disable() impl op and run it from arm_smmu_disable_action() while\nthe CMDQ is still up. That handles a live unbind. A failed reset is already\nhandled because tegra241_vintf_hw_init() deinits the VINTF on its own error\npath. tegra241_cmdqv_remove_vintf() is also used by the iommufd viommu\ndestroy path, so quiesce there too.",
  "id": "GHSA-q92c-jh6h-6xrq",
  "modified": "2026-09-04T18:31:27Z",
  "published": "2026-09-04T18:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80818"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5994617e09ee6016c1b094f29d9c85cac944b477"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9ff145a25c5c8a26b06ef7cf558fb536b18bba6d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a94309bb99eaf0c6a2ace4927864486d19458eb5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d2ab08437e913d9e4dda4dfd0d327446ec8717fc"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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