CVE-2026-46008
Full vulnerability record from the local CVENow database.
Description
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].
View original CVE JSON
{
"id": "CVE-2026-46008",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-05-27T14:17:18.600",
"lastModified": "2026-10-21T13:19:02.227",
"vulnStatus": "Modified",
"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->kdamond so that API callers\nand API functions themselves can show the context is terminated. \ndamos_walk() adds the caller's request to the queue first. After that, it\nshows if the kdamond of the damon_ctx is still running (damon_ctx->kdamond\nis set). Only if the kdamond is running, damos_walk() starts waiting for\nthe kdamond's handling of the newly added request.\n\nThe damos_walk() requests registration and damon_ctx->kdamond unset are\nprotected by different mutexes, though. Hence, damos_walk() could race\nwith damon_ctx->kdamond unset, and result in deadlocks.\n\nFor example, let's 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->kdamond 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->walk_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": "93a7f297362deac614ce3dbbba73ff2ba31aaca3",
"versionType": "git",
"status": "affected"
},
{
"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": "6.18.58",
"lessThanOrEqual": "6.18.*",
"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": "[email protected]",
"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": "[email protected]",
"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"
]
},
{
"url": "https://git.kernel.org/stable/c/93a7f297362deac614ce3dbbba73ff2ba31aaca3",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}