Vulnerability-Lookup

FKIE_CVE-2026-89759

Vulnerability from fkie_nvd - Published: 2026-09-11 20:20 - Updated: 2026-09-11 20:20

Severity

Summary

In the Linux kernel, the following vulnerability has been resolved: mm/kmemleak: avoid soft lockup when scanning task stacks Patch series "mm/kmemleak: avoid soft lockup when scanning task", v3. kmemleak_scan() scans every task stack under one rcu_read_lock() with no reschedule point, which can trip the soft lockup watchdog on hosts with very many threads. That prints the following message, depending on the workload+host configuration: watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [kmemleak:537] scan_block kmemleak_scan kmemleak_scan_thread kthread Patch 1 walks the tasks with find_ge_pid() so the scan reschedules between tasks Patches 2-3 let the scan loops stop early once a scan is interrupted. This patch (of 3): kmemleak_scan() walks every thread and scans its kernel stack under a single rcu_read_lock() with no reschedule point. On a host with very many threads -- amplified by KASAN/lockdep in debug builds -- this loop can hog a CPU long enough to trip the soft lockup watchdog: watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [kmemleak:537] scan_block kmemleak_scan kmemleak_scan_thread kthread A cond_resched() cannot be added directly: the loop runs inside an RCU read-side critical section. Walk the tasks one PID at a time with find_ge_pid(), taking the RCU read lock only to look up and pin each task. The stack is then scanned with no lock held, so cond_resched() runs between tasks and the scan stops early on scan_should_stop(). This follows the next_tgid()/task_seq_get_next() iteration pattern and keeps each RCU critical section short.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/1838c704bcb4fd3556cf67513c6f97a39099e35c
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/3fc8044251de21555fb02c365fa681bab8b0db55
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/5d10d4e19e6daa487f0cd0ea6cba472325de92f9
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/9a1b12c06c192290b8479de48f66f1e75d89c4b7

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/kmemleak.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "9a1b12c06c192290b8479de48f66f1e75d89c4b7",
              "status": "affected",
              "version": "c4b28963fd79457315783b3b0f21c01eb88cfdc1",
              "versionType": "git"
            },
            {
              "lessThan": "3fc8044251de21555fb02c365fa681bab8b0db55",
              "status": "affected",
              "version": "c4b28963fd79457315783b3b0f21c01eb88cfdc1",
              "versionType": "git"
            },
            {
              "lessThan": "1838c704bcb4fd3556cf67513c6f97a39099e35c",
              "status": "affected",
              "version": "c4b28963fd79457315783b3b0f21c01eb88cfdc1",
              "versionType": "git"
            },
            {
              "lessThan": "5d10d4e19e6daa487f0cd0ea6cba472325de92f9",
              "status": "affected",
              "version": "c4b28963fd79457315783b3b0f21c01eb88cfdc1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "mm/kmemleak.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.10"
            },
            {
              "lessThan": "5.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/kmemleak: avoid soft lockup when scanning task stacks\n\nPatch series \"mm/kmemleak: avoid soft lockup when scanning task\", v3.\n\nkmemleak_scan() scans every task stack under one rcu_read_lock() with no\nreschedule point, which can trip the soft lockup watchdog on hosts with\nvery many threads.\n\nThat prints the following message, depending on the workload+host\nconfiguration:\n\n      watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [kmemleak:537]\n       scan_block\n       kmemleak_scan\n       kmemleak_scan_thread\n       kthread\n\nPatch 1 walks the tasks with find_ge_pid() so the scan reschedules between\ntasks\n\nPatches 2-3 let the scan loops stop early once a scan is interrupted.\n\n\nThis patch (of 3):\n\nkmemleak_scan() walks every thread and scans its kernel stack under a\nsingle rcu_read_lock() with no reschedule point.  On a host with very many\nthreads -- amplified by KASAN/lockdep in debug builds -- this loop can hog\na CPU long enough to trip the soft lockup watchdog:\n\n  watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [kmemleak:537]\n   scan_block\n   kmemleak_scan\n   kmemleak_scan_thread\n   kthread\n\nA cond_resched() cannot be added directly: the loop runs inside an RCU\nread-side critical section.\n\nWalk the tasks one PID at a time with find_ge_pid(), taking the RCU read\nlock only to look up and pin each task.  The stack is then scanned with no\nlock held, so cond_resched() runs between tasks and the scan stops early\non scan_should_stop().  This follows the next_tgid()/task_seq_get_next()\niteration pattern and keeps each RCU critical section short."
    }
  ],
  "id": "CVE-2026-89759",
  "lastModified": "2026-09-11T20:20:06.997",
  "metrics": {},
  "published": "2026-09-11T20:20:06.997",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1838c704bcb4fd3556cf67513c6f97a39099e35c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3fc8044251de21555fb02c365fa681bab8b0db55"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5d10d4e19e6daa487f0cd0ea6cba472325de92f9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9a1b12c06c192290b8479de48f66f1e75d89c4b7"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-89759 (GCVE-0-2026-89759)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:47 – Updated: 2026-09-11 19:47

Title

mm/kmemleak: avoid soft lockup when scanning task stacks

Summary

Severity

No CVSS data available.

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/9a1b12c06c192290b…
https://git.kernel.org/stable/c/3fc8044251de21555…
https://git.kernel.org/stable/c/1838c704bcb4fd355…
https://git.kernel.org/stable/c/5d10d4e19e6daa487…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c4b28963fd79457315783b3b0f21c01eb88cfdc1 , < 9a1b12c06c192290b8479de48f66f1e75d89c4b7 (git) Affected: c4b28963fd79457315783b3b0f21c01eb88cfdc1 , < 3fc8044251de21555fb02c365fa681bab8b0db55 (git) Affected: c4b28963fd79457315783b3b0f21c01eb88cfdc1 , < 1838c704bcb4fd3556cf67513c6f97a39099e35c (git) Affected: c4b28963fd79457315783b3b0f21c01eb88cfdc1 , < 5d10d4e19e6daa487f0cd0ea6cba472325de92f9 (git)
Linux	Linux	Affected: 5.10 Unaffected: 0 , < 5.10 (semver) Unaffected: 6.12.109 , ≤ 6.12.* (semver) Unaffected: 6.18.50 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/kmemleak.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "9a1b12c06c192290b8479de48f66f1e75d89c4b7",
              "status": "affected",
              "version": "c4b28963fd79457315783b3b0f21c01eb88cfdc1",
              "versionType": "git"
            },
            {
              "lessThan": "3fc8044251de21555fb02c365fa681bab8b0db55",
              "status": "affected",
              "version": "c4b28963fd79457315783b3b0f21c01eb88cfdc1",
              "versionType": "git"
            },
            {
              "lessThan": "1838c704bcb4fd3556cf67513c6f97a39099e35c",
              "status": "affected",
              "version": "c4b28963fd79457315783b3b0f21c01eb88cfdc1",
              "versionType": "git"
            },
            {
              "lessThan": "5d10d4e19e6daa487f0cd0ea6cba472325de92f9",
              "status": "affected",
              "version": "c4b28963fd79457315783b3b0f21c01eb88cfdc1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "mm/kmemleak.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.10"
            },
            {
              "lessThan": "5.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.109",
                  "versionStartIncluding": "5.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "5.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "5.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "5.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/kmemleak: avoid soft lockup when scanning task stacks\n\nPatch series \"mm/kmemleak: avoid soft lockup when scanning task\", v3.\n\nkmemleak_scan() scans every task stack under one rcu_read_lock() with no\nreschedule point, which can trip the soft lockup watchdog on hosts with\nvery many threads.\n\nThat prints the following message, depending on the workload+host\nconfiguration:\n\n      watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [kmemleak:537]\n       scan_block\n       kmemleak_scan\n       kmemleak_scan_thread\n       kthread\n\nPatch 1 walks the tasks with find_ge_pid() so the scan reschedules between\ntasks\n\nPatches 2-3 let the scan loops stop early once a scan is interrupted.\n\n\nThis patch (of 3):\n\nkmemleak_scan() walks every thread and scans its kernel stack under a\nsingle rcu_read_lock() with no reschedule point.  On a host with very many\nthreads -- amplified by KASAN/lockdep in debug builds -- this loop can hog\na CPU long enough to trip the soft lockup watchdog:\n\n  watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [kmemleak:537]\n   scan_block\n   kmemleak_scan\n   kmemleak_scan_thread\n   kthread\n\nA cond_resched() cannot be added directly: the loop runs inside an RCU\nread-side critical section.\n\nWalk the tasks one PID at a time with find_ge_pid(), taking the RCU read\nlock only to look up and pin each task.  The stack is then scanned with no\nlock held, so cond_resched() runs between tasks and the scan stops early\non scan_should_stop().  This follows the next_tgid()/task_seq_get_next()\niteration pattern and keeps each RCU critical section short."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-11T19:47:01.313Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9a1b12c06c192290b8479de48f66f1e75d89c4b7"
        },
        {
          "url": "https://git.kernel.org/stable/c/3fc8044251de21555fb02c365fa681bab8b0db55"
        },
        {
          "url": "https://git.kernel.org/stable/c/1838c704bcb4fd3556cf67513c6f97a39099e35c"
        },
        {
          "url": "https://git.kernel.org/stable/c/5d10d4e19e6daa487f0cd0ea6cba472325de92f9"
        }
      ],
      "title": "mm/kmemleak: avoid soft lockup when scanning task stacks",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89759",
    "datePublished": "2026-09-11T19:47:01.313Z",
    "dateReserved": "2026-09-11T19:38:34.763Z",
    "dateUpdated": "2026-09-11T19:47:01.313Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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FKIE_CVE-2026-89759

CVE-2026-89759 (GCVE-0-2026-89759)

Tags

Sightings

Nomenclature

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