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GHSA-634R-724X-3G6W

Vulnerability from github – Published: 2026-09-16 12:30 – Updated: 2026-09-16 12:30

Details

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

drm/amdkfd: fix scope of mqd_mgr dereference in pqm_debugfs_mqds

Reading /sys/kernel/debug/kfd/mqds while a process holds an active KFD queue triggers a NULL pointer dereference because the for loop that calls mqd_mgr->debugfs_show_mqd() is incorrectly placed outside the if (pqn->q) block that initializes mqd_mgr.

The queue list can contain entries where pqn->q is NULL (kernel queues where only pqn->kq is valid). In the original code:

if (pqn->q) { ... mqd_mgr = q->device->dqm->mqd_mgrs[mqd_type]; size = mqd_mgr->mqd_stride(...); }

for (xcc = 0; xcc < num_xccs; xcc++) { // WRONG: outside if block mqd = q->mqd + size * xcc; r = mqd_mgr->debugfs_show_mqd(m, mqd); }

When iterating over a queue node where pqn->q is NULL: 1. The if (pqn->q) block is skipped 2. mqd_mgr remains uninitialized (NULL from declaration) 3. The for loop executes anyway 4. mqd_mgr->debugfs_show_mqd(m, mqd) dereferences NULL

The crash manifests as:

BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode RIP: 0010:0x0 Call Trace: pqm_debugfs_mqds+0x10c/0x1d0 [amdgpu] kfd_debugfs_mqds_by_process+0x9b/0x110 [amdgpu] seq_read_iter+0x132/0x4b0 ...

Fix by moving the for loop inside the if (pqn->q) block, so mqd_mgr and related variables are only used when properly initialized.

(cherry picked from commit 8bfe29d5c798940f797aa24135d2734c3ffce9de)

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{
  "affected": [],
  "aliases": [
    "CVE-2026-89809"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-16T11:16:46Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdkfd: fix scope of mqd_mgr dereference in pqm_debugfs_mqds\n\nReading /sys/kernel/debug/kfd/mqds while a process holds an active KFD\nqueue triggers a NULL pointer dereference because the for loop that\ncalls mqd_mgr-\u003edebugfs_show_mqd() is incorrectly placed outside the\nif (pqn-\u003eq) block that initializes mqd_mgr.\n\nThe queue list can contain entries where pqn-\u003eq is NULL (kernel queues\nwhere only pqn-\u003ekq is valid). In the original code:\n\n  if (pqn-\u003eq) {\n      ...\n      mqd_mgr = q-\u003edevice-\u003edqm-\u003emqd_mgrs[mqd_type];\n      size = mqd_mgr-\u003emqd_stride(...);\n  }\n\n  for (xcc = 0; xcc \u003c num_xccs; xcc++) {  // WRONG: outside if block\n      mqd = q-\u003emqd + size * xcc;\n      r = mqd_mgr-\u003edebugfs_show_mqd(m, mqd);\n  }\n\nWhen iterating over a queue node where pqn-\u003eq is NULL:\n1. The if (pqn-\u003eq) block is skipped\n2. mqd_mgr remains uninitialized (NULL from declaration)\n3. The for loop executes anyway\n4. mqd_mgr-\u003edebugfs_show_mqd(m, mqd) dereferences NULL\n\nThe crash manifests as:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000000\n  #PF: supervisor instruction fetch in kernel mode\n  RIP: 0010:0x0\n  Call Trace:\n   pqm_debugfs_mqds+0x10c/0x1d0 [amdgpu]\n   kfd_debugfs_mqds_by_process+0x9b/0x110 [amdgpu]\n   seq_read_iter+0x132/0x4b0\n   ...\n\nFix by moving the for loop inside the if (pqn-\u003eq) block, so mqd_mgr\nand related variables are only used when properly initialized.\n\n(cherry picked from commit 8bfe29d5c798940f797aa24135d2734c3ffce9de)",
  "id": "GHSA-634r-724x-3g6w",
  "modified": "2026-09-16T12:30:37Z",
  "published": "2026-09-16T12:30:37Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89809"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/012a026bae0212952b423a842b7e2c0bf21f8e7a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/58e866711b234571b0ce342c43d153a4786b32b8"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-89809 (GCVE-0-2026-89809)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:30 – Updated: 2026-09-17 09:29

Title

drm/amdkfd: fix scope of mqd_mgr dereference in pqm_debugfs_mqds

Summary

In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: fix scope of mqd_mgr dereference in pqm_debugfs_mqds Reading /sys/kernel/debug/kfd/mqds while a process holds an active KFD queue triggers a NULL pointer dereference because the for loop that calls mqd_mgr->debugfs_show_mqd() is incorrectly placed outside the if (pqn->q) block that initializes mqd_mgr. The queue list can contain entries where pqn->q is NULL (kernel queues where only pqn->kq is valid). In the original code: if (pqn->q) { ... mqd_mgr = q->device->dqm->mqd_mgrs[mqd_type]; size = mqd_mgr->mqd_stride(...); } for (xcc = 0; xcc < num_xccs; xcc++) { // WRONG: outside if block mqd = q->mqd + size * xcc; r = mqd_mgr->debugfs_show_mqd(m, mqd); } When iterating over a queue node where pqn->q is NULL: 1. The if (pqn->q) block is skipped 2. mqd_mgr remains uninitialized (NULL from declaration) 3. The for loop executes anyway 4. mqd_mgr->debugfs_show_mqd(m, mqd) dereferences NULL The crash manifests as: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode RIP: 0010:0x0 Call Trace: pqm_debugfs_mqds+0x10c/0x1d0 [amdgpu] kfd_debugfs_mqds_by_process+0x9b/0x110 [amdgpu] seq_read_iter+0x132/0x4b0 ... Fix by moving the for loop inside the if (pqn->q) block, so mqd_mgr and related variables are only used when properly initialized. (cherry picked from commit 8bfe29d5c798940f797aa24135d2734c3ffce9de)

Severity

No CVSS data available.

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/58e866711b234571b…
https://git.kernel.org/stable/c/012a026bae0212952…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: e1b73b64271d706079370b58b81292dafd373163 , < 58e866711b234571b0ce342c43d153a4786b32b8 (git) Affected: e1b73b64271d706079370b58b81292dafd373163 , < 012a026bae0212952b423a842b7e2c0bf21f8e7a (git)
Linux	Linux	Affected: 7.0 Unaffected: 0 , < 7.0 (semver) Unaffected: 7.2.5 , ≤ 7.2.* (semver) Unaffected: 7.3-rc2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/amdkfd/kfd_process_queue_manager.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "58e866711b234571b0ce342c43d153a4786b32b8",
              "status": "affected",
              "version": "e1b73b64271d706079370b58b81292dafd373163",
              "versionType": "git"
            },
            {
              "lessThan": "012a026bae0212952b423a842b7e2c0bf21f8e7a",
              "status": "affected",
              "version": "e1b73b64271d706079370b58b81292dafd373163",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/amd/amdkfd/kfd_process_queue_manager.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.0"
            },
            {
              "lessThan": "7.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "7.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "7.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
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        }
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdkfd: fix scope of mqd_mgr dereference in pqm_debugfs_mqds\n\nReading /sys/kernel/debug/kfd/mqds while a process holds an active KFD\nqueue triggers a NULL pointer dereference because the for loop that\ncalls mqd_mgr-\u003edebugfs_show_mqd() is incorrectly placed outside the\nif (pqn-\u003eq) block that initializes mqd_mgr.\n\nThe queue list can contain entries where pqn-\u003eq is NULL (kernel queues\nwhere only pqn-\u003ekq is valid). In the original code:\n\n  if (pqn-\u003eq) {\n      ...\n      mqd_mgr = q-\u003edevice-\u003edqm-\u003emqd_mgrs[mqd_type];\n      size = mqd_mgr-\u003emqd_stride(...);\n  }\n\n  for (xcc = 0; xcc \u003c num_xccs; xcc++) {  // WRONG: outside if block\n      mqd = q-\u003emqd + size * xcc;\n      r = mqd_mgr-\u003edebugfs_show_mqd(m, mqd);\n  }\n\nWhen iterating over a queue node where pqn-\u003eq is NULL:\n1. The if (pqn-\u003eq) block is skipped\n2. mqd_mgr remains uninitialized (NULL from declaration)\n3. The for loop executes anyway\n4. mqd_mgr-\u003edebugfs_show_mqd(m, mqd) dereferences NULL\n\nThe crash manifests as:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000000\n  #PF: supervisor instruction fetch in kernel mode\n  RIP: 0010:0x0\n  Call Trace:\n   pqm_debugfs_mqds+0x10c/0x1d0 [amdgpu]\n   kfd_debugfs_mqds_by_process+0x9b/0x110 [amdgpu]\n   seq_read_iter+0x132/0x4b0\n   ...\n\nFix by moving the for loop inside the if (pqn-\u003eq) block, so mqd_mgr\nand related variables are only used when properly initialized.\n\n(cherry picked from commit 8bfe29d5c798940f797aa24135d2734c3ffce9de)"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-17T09:29:07.472Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/012a026bae0212952b423a842b7e2c0bf21f8e7a"
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      ],
      "title": "drm/amdkfd: fix scope of mqd_mgr dereference in pqm_debugfs_mqds",
      "x_generator": {
        "engine": "bippy-1.2.0"
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    }
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89809",
    "datePublished": "2026-09-16T10:30:42.445Z",
    "dateReserved": "2026-09-11T19:38:34.767Z",
    "dateUpdated": "2026-09-17T09:29:07.472Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

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GHSA-634R-724X-3G6W

CVE-2026-89809 (GCVE-0-2026-89809)

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