CVE-2026-31445 (GCVE-0-2026-31445)
Vulnerability from cvelistv5 – Published: 2026-04-22 13:53 – Updated: 2026-04-22 13:53
VLAI?
Title
mm/damon/core: avoid use of half-online-committed context
Summary
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/core: avoid use of half-online-committed context
One major usage of damon_call() is online DAMON parameters update. It is
done by calling damon_commit_ctx() inside the damon_call() callback
function. damon_commit_ctx() can fail for two reasons: 1) invalid
parameters and 2) internal memory allocation failures. In case of
failures, the damon_ctx that attempted to be updated (commit destination)
can be partially updated (or, corrupted from a perspective), and therefore
shouldn't be used anymore. The function only ensures the damon_ctx object
can safely deallocated using damon_destroy_ctx().
The API callers are, however, calling damon_commit_ctx() only after
asserting the parameters are valid, to avoid damon_commit_ctx() fails due
to invalid input parameters. But it can still theoretically fail if the
internal memory allocation fails. In the case, DAMON may run with the
partially updated damon_ctx. This can result in unexpected behaviors
including even NULL pointer dereference in case of damos_commit_dests()
failure [1]. Such allocation failure is arguably too small to fail, so
the real world impact would be rare. But, given the bad consequence, this
needs to be fixed.
Avoid such partially-committed (maybe-corrupted) damon_ctx use by saving
the damon_commit_ctx() failure on the damon_ctx object. For this,
introduce damon_ctx->maybe_corrupted field. damon_commit_ctx() sets it
when it is failed. kdamond_call() checks if the field is set after each
damon_call_control->fn() is executed. If it is set, ignore remaining
callback requests and return. All kdamond_call() callers including
kdamond_fn() also check the maybe_corrupted field right after
kdamond_call() invocations. If the field is set, break the kdamond_fn()
main loop so that DAMON sill doesn't use the context that might be
corrupted.
[sj@kernel.org: let kdamond_call() with cancel regardless of maybe_corrupted]
Severity ?
No CVSS data available.
Assigner
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Affected:
3301f1861d34f53911a30a8f5f41b9141bd8ed39 , < 9c495f9d3781cd692bd199531cabd4627155e8cd
(git)
Affected: 3301f1861d34f53911a30a8f5f41b9141bd8ed39 , < 1b247cd0654a3a306996fa80741d79296c683a56 (git) Affected: 3301f1861d34f53911a30a8f5f41b9141bd8ed39 , < 26f775a054c3cda86ad465a64141894a90a9e145 (git) |
||
{
"containers": {
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{
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"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": [
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"status": "affected",
"version": "3301f1861d34f53911a30a8f5f41b9141bd8ed39",
"versionType": "git"
},
{
"lessThan": "1b247cd0654a3a306996fa80741d79296c683a56",
"status": "affected",
"version": "3301f1861d34f53911a30a8f5f41b9141bd8ed39",
"versionType": "git"
},
{
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"status": "affected",
"version": "3301f1861d34f53911a30a8f5f41b9141bd8ed39",
"versionType": "git"
}
]
},
{
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"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": "6.15"
},
{
"lessThan": "6.15",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.21",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.11",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
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"versionEndExcluding": "6.18.21",
"versionStartIncluding": "6.15",
"vulnerable": true
},
{
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}
],
"negate": false,
"operator": "OR"
}
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}
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"descriptions": [
{
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/core: avoid use of half-online-committed context\n\nOne major usage of damon_call() is online DAMON parameters update. It is\ndone by calling damon_commit_ctx() inside the damon_call() callback\nfunction. damon_commit_ctx() can fail for two reasons: 1) invalid\nparameters and 2) internal memory allocation failures. In case of\nfailures, the damon_ctx that attempted to be updated (commit destination)\ncan be partially updated (or, corrupted from a perspective), and therefore\nshouldn\u0027t be used anymore. The function only ensures the damon_ctx object\ncan safely deallocated using damon_destroy_ctx().\n\nThe API callers are, however, calling damon_commit_ctx() only after\nasserting the parameters are valid, to avoid damon_commit_ctx() fails due\nto invalid input parameters. But it can still theoretically fail if the\ninternal memory allocation fails. In the case, DAMON may run with the\npartially updated damon_ctx. This can result in unexpected behaviors\nincluding even NULL pointer dereference in case of damos_commit_dests()\nfailure [1]. Such allocation failure is arguably too small to fail, so\nthe real world impact would be rare. But, given the bad consequence, this\nneeds to be fixed.\n\nAvoid such partially-committed (maybe-corrupted) damon_ctx use by saving\nthe damon_commit_ctx() failure on the damon_ctx object. For this,\nintroduce damon_ctx-\u003emaybe_corrupted field. damon_commit_ctx() sets it\nwhen it is failed. kdamond_call() checks if the field is set after each\ndamon_call_control-\u003efn() is executed. If it is set, ignore remaining\ncallback requests and return. All kdamond_call() callers including\nkdamond_fn() also check the maybe_corrupted field right after\nkdamond_call() invocations. If the field is set, break the kdamond_fn()\nmain loop so that DAMON sill doesn\u0027t use the context that might be\ncorrupted.\n\n[sj@kernel.org: let kdamond_call() with cancel regardless of maybe_corrupted]"
}
],
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"dateUpdated": "2026-04-22T13:53:42.090Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
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"references": [
{
"url": "https://git.kernel.org/stable/c/9c495f9d3781cd692bd199531cabd4627155e8cd"
},
{
"url": "https://git.kernel.org/stable/c/1b247cd0654a3a306996fa80741d79296c683a56"
},
{
"url": "https://git.kernel.org/stable/c/26f775a054c3cda86ad465a64141894a90a9e145"
}
],
"title": "mm/damon/core: avoid use of half-online-committed context",
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"cveId": "CVE-2026-31445",
"datePublished": "2026-04-22T13:53:42.090Z",
"dateReserved": "2026-03-09T15:48:24.090Z",
"dateUpdated": "2026-04-22T13:53:42.090Z",
"state": "PUBLISHED"
},
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"date": "2026-04-23",
"epss": "0.00017",
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}
}
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Sightings
| Author | Source | Type | Date |
|---|
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.
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