FKIE_CVE-2026-90006

Vulnerability from fkie_nvd - Published: 2026-09-16 11:17 - Updated: 2026-10-19 09:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: samples/damon/mtier: handle damon_stop() failure damon_sample_mtier_stop() assumes its damon_stop() call will always successfully stops the two DAMON contexts. Hence it deallocates the two DAMON contexts after the damon_stop() call. However, if a given context is already stopped, damon_stop() fails and returns an error while letting the DAMON contexts that have not yet stopped keep running. This kind of unexpected early DAMON context stops could happen due to memory allocation failures in kdamond_fn(). Because damon_sample_mtier_stop() just deallocates all DAMON contexts with damon_target and damon_region objects that are linked to the contexts, the execution of the unstopped DAMON context (kdamond) ends up using the memory that freed (use-after-free). Fix the issue by separating the damon_stop() to be invoked per context. Note that DAMON_SYSFS also allows multiple DAMON contexts execution. But, it calls damon_stop() for each context one by one. Hence this issue is only in mtier. For the long term, it would be better to refactor damon_stop() to always ensure stopping all contexts regardless of the failures in the middle. Make this fix in the current way, though, to keep it simple and easy to backport. I will do the refactoring later. The issue was discovered [1] by Sashiko.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/215f9a7e4f1dcfc05ebcdc5c1ad0ea0dcb47bd09
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3c07c57b894116ae26f01b84c68e68b538ada7ed
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9dc5b6d66fd51b103eff21ed0df3e292f489ebc0
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "samples/damon/mtier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3c07c57b894116ae26f01b84c68e68b538ada7ed",
              "status": "affected",
              "version": "82a08bde3cf7bbbe90de57baa181bebf676582c7",
              "versionType": "git"
            },
            {
              "lessThan": "215f9a7e4f1dcfc05ebcdc5c1ad0ea0dcb47bd09",
              "status": "affected",
              "version": "82a08bde3cf7bbbe90de57baa181bebf676582c7",
              "versionType": "git"
            },
            {
              "lessThan": "9dc5b6d66fd51b103eff21ed0df3e292f489ebc0",
              "status": "affected",
              "version": "82a08bde3cf7bbbe90de57baa181bebf676582c7",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "samples/damon/mtier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "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\nsamples/damon/mtier: handle damon_stop() failure\n\ndamon_sample_mtier_stop() assumes its damon_stop() call will always\nsuccessfully stops the two DAMON contexts.  Hence it deallocates the two\nDAMON contexts after the damon_stop() call.  However, if a given context\nis already stopped, damon_stop() fails and returns an error while letting\nthe DAMON contexts that have not yet stopped keep running.  This kind of\nunexpected early DAMON context stops could happen due to memory allocation\nfailures in kdamond_fn().  Because damon_sample_mtier_stop() just\ndeallocates all DAMON contexts with damon_target and damon_region objects\nthat are linked to the contexts, the execution of the unstopped DAMON\ncontext (kdamond) ends up using the memory that freed (use-after-free). \nFix the issue by separating the damon_stop() to be invoked per context.\n\nNote that DAMON_SYSFS also allows multiple DAMON contexts execution.  But,\nit calls damon_stop() for each context one by one.  Hence this issue is\nonly in mtier.\n\nFor the long term, it would be better to refactor damon_stop() to always\nensure stopping all contexts regardless of the failures in the middle. \nMake this fix in the current way, though, to keep it simple and easy to\nbackport.  I will do the refactoring later.\n\nThe issue was discovered [1] by Sashiko."
    }
  ],
  "id": "CVE-2026-90006",
  "lastModified": "2026-10-19T09:18:48.317",
  "metrics": {},
  "published": "2026-09-16T11:17:13.213",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/215f9a7e4f1dcfc05ebcdc5c1ad0ea0dcb47bd09"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3c07c57b894116ae26f01b84c68e68b538ada7ed"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9dc5b6d66fd51b103eff21ed0df3e292f489ebc0"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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