CVE-2026-46008 (GCVE-0-2026-46008)

Vulnerability from cvelistv5 – Published: 2026-05-27 12:56 – Updated: 2026-06-14 17:47
VLAI
Title
mm/damon/core: fix damos_walk() vs kdamond_fn() exit race
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/damon/core: fix damos_walk() vs kdamond_fn() exit race When kdamond_fn() main loop is finished, the function cancels remaining damos_walk() request and unset the damon_ctx->kdamond so that API callers and API functions themselves can show the context is terminated. damos_walk() adds the caller's request to the queue first. After that, it shows if the kdamond of the damon_ctx is still running (damon_ctx->kdamond is set). Only if the kdamond is running, damos_walk() starts waiting for the kdamond's handling of the newly added request. The damos_walk() requests registration and damon_ctx->kdamond unset are protected by different mutexes, though. Hence, damos_walk() could race with damon_ctx->kdamond unset, and result in deadlocks. For example, let's suppose kdamond successfully finished the damow_walk() request cancelling. Right after that, damos_walk() is called for the context. It registers the new request, and shows the context is still running, because damon_ctx->kdamond unset is not yet done. Hence the damos_walk() caller starts waiting for the handling of the request. However, the kdamond is already on the termination steps, so it never handles the new request. As a result, the damos_walk() caller thread infinitely waits. Fix this by introducing another damon_ctx field, namely walk_control_obsolete. It is protected by the damon_ctx->walk_control_lock, which protects damos_walk() request registration. Initialize (unset) it in kdamond_fn() before letting damon_start() returns and set it just before the cancelling of the remaining damos_walk() request is executed. damos_walk() reads the obsolete field under the lock and avoids adding a new request. After this change, only requests that are guaranteed to be handled or cancelled are registered. Hence the after-registration DAMON context termination check is no longer needed. Remove it together. The issue is found by sashiko [1].
Severity
4.7 (Medium)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: bf0eaba0ff9c9c8e6fd58ddfa1a8b6df4b813f61 , < 0ba956a239ba6e3fae8555d3660e22e675be63b5 (git)
Affected: bf0eaba0ff9c9c8e6fd58ddfa1a8b6df4b813f61 , < 33c3f6c2b48cd84b441dba1ee3e62290e53930f4 (git)
Create a notification for this product.
Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 7.0.4 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/damon.h",
            "mm/damon/core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0ba956a239ba6e3fae8555d3660e22e675be63b5",
              "status": "affected",
              "version": "bf0eaba0ff9c9c8e6fd58ddfa1a8b6df4b813f61",
              "versionType": "git"
            },
            {
              "lessThan": "33c3f6c2b48cd84b441dba1ee3e62290e53930f4",
              "status": "affected",
              "version": "bf0eaba0ff9c9c8e6fd58ddfa1a8b6df4b813f61",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/linux/damon.h",
            "mm/damon/core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.4",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/core: fix damos_walk() vs kdamond_fn() exit race\n\nWhen kdamond_fn() main loop is finished, the function cancels remaining\ndamos_walk() request and unset the damon_ctx-\u003ekdamond so that API callers\nand API functions themselves can show the context is terminated. \ndamos_walk() adds the caller\u0027s request to the queue first.  After that, it\nshows if the kdamond of the damon_ctx is still running (damon_ctx-\u003ekdamond\nis set).  Only if the kdamond is running, damos_walk() starts waiting for\nthe kdamond\u0027s handling of the newly added request.\n\nThe damos_walk() requests registration and damon_ctx-\u003ekdamond unset are\nprotected by different mutexes, though.  Hence, damos_walk() could race\nwith damon_ctx-\u003ekdamond unset, and result in deadlocks.\n\nFor example, let\u0027s suppose kdamond successfully finished the damow_walk()\nrequest cancelling.  Right after that, damos_walk() is called for the\ncontext.  It registers the new request, and shows the context is still\nrunning, because damon_ctx-\u003ekdamond unset is not yet done.  Hence the\ndamos_walk() caller starts waiting for the handling of the request. \nHowever, the kdamond is already on the termination steps, so it never\nhandles the new request.  As a result, the damos_walk() caller thread\ninfinitely waits.\n\nFix this by introducing another damon_ctx field, namely\nwalk_control_obsolete.  It is protected by the\ndamon_ctx-\u003ewalk_control_lock, which protects damos_walk() request\nregistration.  Initialize (unset) it in kdamond_fn() before letting\ndamon_start() returns and set it just before the cancelling of the\nremaining damos_walk() request is executed.  damos_walk() reads the\nobsolete field under the lock and avoids adding a new request.\n\nAfter this change, only requests that are guaranteed to be handled or\ncancelled are registered.  Hence the after-registration DAMON context\ntermination check is no longer needed.  Remove it together.\n\nThe issue is found by sashiko [1]."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-14T17:47:40.288Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/0ba956a239ba6e3fae8555d3660e22e675be63b5"
        },
        {
          "url": "https://git.kernel.org/stable/c/33c3f6c2b48cd84b441dba1ee3e62290e53930f4"
        }
      ],
      "title": "mm/damon/core: fix damos_walk() vs kdamond_fn() exit race",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46008",
    "datePublished": "2026-05-27T12:56:08.315Z",
    "dateReserved": "2026-05-13T15:03:33.092Z",
    "dateUpdated": "2026-06-14T17:47:40.288Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-46008",
      "date": "2026-08-14",
      "epss": "0.00079",
      "percentile": "0.00168"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-46008\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-27T14:17:18.600\",\"lastModified\":\"2026-06-17T10:52:53.427\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nmm/damon/core: fix damos_walk() vs kdamond_fn() exit race\\n\\nWhen kdamond_fn() main loop is finished, the function cancels remaining\\ndamos_walk() request and unset the damon_ctx-\u003ekdamond so that API callers\\nand API functions themselves can show the context is terminated. \\ndamos_walk() adds the caller\u0027s request to the queue first.  After that, it\\nshows if the kdamond of the damon_ctx is still running (damon_ctx-\u003ekdamond\\nis set).  Only if the kdamond is running, damos_walk() starts waiting for\\nthe kdamond\u0027s handling of the newly added request.\\n\\nThe damos_walk() requests registration and damon_ctx-\u003ekdamond unset are\\nprotected by different mutexes, though.  Hence, damos_walk() could race\\nwith damon_ctx-\u003ekdamond unset, and result in deadlocks.\\n\\nFor example, let\u0027s suppose kdamond successfully finished the damow_walk()\\nrequest cancelling.  Right after that, damos_walk() is called for the\\ncontext.  It registers the new request, and shows the context is still\\nrunning, because damon_ctx-\u003ekdamond unset is not yet done.  Hence the\\ndamos_walk() caller starts waiting for the handling of the request. \\nHowever, the kdamond is already on the termination steps, so it never\\nhandles the new request.  As a result, the damos_walk() caller thread\\ninfinitely waits.\\n\\nFix this by introducing another damon_ctx field, namely\\nwalk_control_obsolete.  It is protected by the\\ndamon_ctx-\u003ewalk_control_lock, which protects damos_walk() request\\nregistration.  Initialize (unset) it in kdamond_fn() before letting\\ndamon_start() returns and set it just before the cancelling of the\\nremaining damos_walk() request is executed.  damos_walk() reads the\\nobsolete field under the lock and avoids adding a new request.\\n\\nAfter this change, only requests that are guaranteed to be handled or\\ncancelled are registered.  Hence the after-registration DAMON context\\ntermination check is no longer needed.  Remove it together.\\n\\nThe issue is found by sashiko [1].\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"include/linux/damon.h\",\"mm/damon/core.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"bf0eaba0ff9c9c8e6fd58ddfa1a8b6df4b813f61\",\"lessThan\":\"0ba956a239ba6e3fae8555d3660e22e675be63b5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bf0eaba0ff9c9c8e6fd58ddfa1a8b6df4b813f61\",\"lessThan\":\"33c3f6c2b48cd84b441dba1ee3e62290e53930f4\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"include/linux/damon.h\",\"mm/damon/core.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.14\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.14\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.0.4\",\"lessThanOrEqual\":\"7.0.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":4.7,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.0,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-362\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.14\",\"versionEndExcluding\":\"7.0.4\",\"matchCriteriaId\":\"241B688D-8E14-4010-AB9E-D5F5E52FA273\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0ba956a239ba6e3fae8555d3660e22e675be63b5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/33c3f6c2b48cd84b441dba1ee3e62290e53930f4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]}]}}",
    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-06-28T07:40:29+00:00",
      "cve": "CVE-2026-46008",
      "id": "CVE-2026-46008",
      "initial_release_date": "2026-05-27T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: mm/damon/core: fix damos_walk() vs kdamond_fn() exit race",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46008.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-06-15T01:25:33Z",
      "cve": "CVE-2026-46008",
      "id": "CVE-2026-46008",
      "initial_release_date": "2026-05-28T03:54:29Z",
      "product_status:known_not_affected": "291",
      "product_status:recommended": "4",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-46008",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-46008.json",
      "version": "4"
    }
  }
}