linux — security advisory
In the Linux kernel, the following vulnerability has been resolved: mm: swap: fix race between free_swap_and_cache() and swapoff() There was previously a theoretical window where swapoff() could run and teardown a swap_info_struct while a call to free_swap_and_cache() was running in another thread. This could cause, amongst other bad possibilities, swap_page_trans_huge_swapped() (called by free_swap_and_cache()) to access the freed memory for swap_map. This is a theoretical problem and I haven't been able to provoke it from a test case. But there has been agreement based on code review that this is possible (see link below). Fix it by using get_swap_device()/put_swap_device(), which will stall swapoff(). There was an extra check in _swap_info_get() to confirm that the swap entry was not free. This isn't present in get_swap_device() because it doesn't make sense in general due to the race between getting the reference and swapoff. So I've added an equivalent check directly in free_swap_and_cache(). Details of how to provoke one possible issue (thanks to David Hildenbrand for deriving this): --8<----- __swap_entry_free() might be the last user and result in "count == SWAP_HAS_CACHE". swapoff->try_to_unuse() will stop as soon as soon as si->inuse_pages==0. So the question is: could someone reclaim the folio and turn si->inuse_pages==0, before we completed swap_page_trans_huge_swapped(). Imagine the following: 2 MiB folio in the swapcache. Only 2 subpages are still references by
- Products
- linux
- Affected versions
- 6.1.27-1, 6.1.37-1, 6.1.38-1, 6.1.38-2, 6.1.38-2~bpo11+1, 6.1.38-3, 6.1.38-4, 6.1.38-4~bpo11+1, 6.1.52-1, 6.1.55-1, 6.1.55-1~bpo11+1, 6.1.64-1, 6.1.66-1, 6.1.67-1, 6.1.69-1, 6.1.69-1~bpo11+1, 6.1.76-1, 6.1.76-1~bpo11+1, 6.1.82-1
- Fixed versions
- 6.1.85-1, 6.7.12-1
- CVEs
- CVE-2024-26960
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 30 Oct 2026, 16:22 UTC · Revision 1
Source evidence
In the Linux kernel, the following vulnerability has been resolved: mm: swap: fix race between free_swap_and_cache() and swapoff() There was previously a theoretical window where swapoff() could run and teardown a swap_info_struct while a call to free_swap_and_cache() was running in another thread. This could cause, amongst other bad possibilities, swap_page_trans_huge_swapped() (called by free_swap_and_cache()) to access the freed memory for swap_map. This is a theoretical problem and I haven't been able to provoke it from a test case. But there has been agreement based on code review that this is possible (see link below). Fix it by using get_swap_device()/put_swap_device(), which will stall swapoff(). There was an extra check in _swap_info_get() to confirm that the swap entry was not free. This isn't present in get_swap_device() because it doesn't make sense in general due to the race between getting the reference and swapoff. So I've added an equivalent check directly in free_swap_and_cache(). Details of how to provoke one possible issue (thanks to David Hildenbrand for deriving this): --8<----- __swap_entry_free() might be the last user and result in "count == SWAP_HAS_CACHE". swapoff->try_to_unuse() will stop as soon as soon as si->inuse_pages==0. So the question is: could someone reclaim the folio and turn si->inuse_pages==0, before we completed swap_page_trans_huge_swapped(). Imagine the following: 2 MiB folio in the swapcache. Only 2 subpages are still references by
osv:DEBIAN-CVE-2024-26960
linux
Fixed versions: 6.1.85-1
linux
Fixed versions: 6.7.12-1
linux
Fixed versions: 6.7.12-1
Complete source record
{
"id": "b6c4b6a3b39bb4217e5465058f31774393b0a8b7c7ff98d2a4486ff700bb3e70",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2024-26960",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2024-26960",
"summary": "In the Linux kernel, the following vulnerability has been resolved: mm: swap: fix race between free_swap_and_cache() and swapoff() There was previously a theoretical window where swapoff() could run and teardown a swap_info_struct while a call to free_swap_and_cache() was running in another thread. This could cause, amongst other bad possibilities, swap_page_trans_huge_swapped() (called by free_swap_and_cache()) to access the freed memory for swap_map. This is a theoretical problem and I haven't been able to provoke it from a test case. But there has been agreement based on code review that this is possible (see link below). Fix it by using get_swap_device()/put_swap_device(), which will stall swapoff(). There was an extra check in _swap_info_get() to confirm that the swap entry was not free. This isn't present in get_swap_device() because it doesn't make sense in general due to the race between getting the reference and swapoff. So I've added an equivalent check directly in free_swap_and_cache(). Details of how to provoke one possible issue (thanks to David Hildenbrand for deriving this): --8<----- __swap_entry_free() might be the last user and result in \"count == SWAP_HAS_CACHE\". swapoff->try_to_unuse() will stop as soon as soon as si->inuse_pages==0. So the question is: could someone reclaim the folio and turn si->inuse_pages==0, before we completed swap_page_trans_huge_swapped(). Imagine the following: 2 MiB folio in the swapcache. Only 2 subpages are still references by ",
"evidence": "osv:DEBIAN-CVE-2024-26960",
"products": [
{
"name": {
"value": "linux",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "6.1.85-1",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "6.1.27-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.37-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.38-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.38-2",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.38-2~bpo11+1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.38-3",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.38-4",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.38-4~bpo11+1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.52-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.55-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.55-1~bpo11+1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.64-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.66-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.67-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.69-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.69-1~bpo11+1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.76-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.76-1~bpo11+1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.82-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
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"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "6.7.12-1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "linux",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "6.7.12-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2024-26960",
"aliases": [
"DEBIAN-CVE-2024-26960"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "6.1.85-1"
}
]
}
],
"package": {
"name": "linux",
"purl": "pkg:deb/debian/linux?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"6.1.27-1",
"6.1.37-1",
"6.1.38-1",
"6.1.38-2",
"6.1.38-2~bpo11+1",
"6.1.38-3",
"6.1.38-4",
"6.1.38-4~bpo11+1",
"6.1.52-1",
"6.1.55-1",
"6.1.55-1~bpo11+1",
"6.1.64-1",
"6.1.66-1",
"6.1.67-1",
"6.1.69-1",
"6.1.69-1~bpo11+1",
"6.1.76-1",
"6.1.76-1~bpo11+1",
"6.1.82-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2024-26960.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "6.7.12-1"
}
]
}
],
"package": {
"name": "linux",
"purl": "pkg:deb/debian/linux?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2024-26960.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "6.7.12-1"
}
]
}
],
"package": {
"name": "linux",
"purl": "pkg:deb/debian/linux?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2024-26960.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-15T09:47:31.327523897Z",
"provider": "osv",
"upstream": [
"CVE-2024-26960"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2024-26960"
]
},
"related_cves": [
{
"value": "CVE-2024-26960",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 327592,
"published_at": "2024-05-01T06:15:12.323+00:00"
}