CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
9.5%
In the Linux kernel, the following vulnerability has been resolved:
mm: fix crashes from deferred split racing folio migration
Even on 6.10-rc6, I’ve been seeing elusive "Bad page state"s (often on
flags when freeing, yet the flags shown are not bad: PG_locked had been
set and cleared??), and VM_BUG_ON_PAGE(page_ref_count(page) == 0)s from
deferred_split_scan()'s folio_put(), and a variety of other BUG and WARN
symptoms implying double free by deferred split and large folio migration.
6.7 commit 9bcef5973e31 (“mm: memcg: fix split queue list crash when large
folio migration”) was right to fix the memcg-dependent locking broken in
85ce2c517ade (“memcontrol: only transfer the memcg data for migration”),
but missed a subtlety of deferred_split_scan(): it moves folios to its own
local list to work on them without split_queue_lock, during which time
folio->_deferred_list is not empty, but even the “right” lock does nothing
to secure the folio and the list it is on.
Fortunately, deferred_split_scan() is careful to use folio_try_get(): so
folio_migrate_mapping() can avoid the race by folio_undo_large_rmappable()
while the old folio’s reference count is temporarily frozen to 0 - adding
such a freeze in the !mapping case too (originally, folio lock and
unmapping and no swap cache left an anon folio unreachable, so no freezing
was needed there: but the deferred split queue offers a way to reach it).
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
ubuntu | 24.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux-azure | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-bluefield | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux-gcp | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux-gke | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-hwe-6.8 | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux-ibm | < any | UNKNOWN |
ubuntu | 24.04 | noarch | linux-lowlatency | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-lowlatency-hwe-6.8 | < any | UNKNOWN |
git.kernel.org/linus/be9581ea8c058d81154251cb0695987098996cad (6.10)
git.kernel.org/stable/c/be9581ea8c058d81154251cb0695987098996cad
git.kernel.org/stable/c/fc7facce686b64201dbf0b9614cc1d0bfad70010
launchpad.net/bugs/cve/CVE-2024-42234
nvd.nist.gov/vuln/detail/CVE-2024-42234
security-tracker.debian.org/tracker/CVE-2024-42234
www.cve.org/CVERecord?id=CVE-2024-42234