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CVE-2026-89647: Linux

7.5

CVSS 3.1

Няма данни

Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)

Няма потвърждение

Атакува се

Няма данни

Време до експлоатация

Атакува се по мрежата, без особени условия, без вход и без действие от потребителя.

  • Експлоатация: няма данни за експлоатация
  • Атаката може да се автоматизира

Описание

Оригинално описание

In the Linux kernel, the following vulnerability has been resolved: ceph: do not repeat ceph_trim_dentries() if no progress possible ceph_cap_reclaim_work() re-queues itself for as long as ceph_trim_dentries() returns -EAGAIN, which happens whenever a lease walk exhausts its `nr_to_scan` budget. This creates a busy loop that consumes CPU without making any progress when there is nothing to reclaim: with no cap pressure (`count==0`) and every scanned lease still valid, each pass runs the full scan budget down to zero and returns `-EAGAIN`, only to be queued again immediately. The dir-lease walk made this worse. When `expire_dir_lease` is `false` (i.e. we have no intention of reclaiming dir leases), __dir_lease_check() returned `TOUCH` for every valid lease. `TOUCH` moves the dentry to the tail of the list and resets `di->time` via __dentry_dir_lease_touch(), so a walk over N valid leases pointlessly rewrote the list, refreshed the timestamps (preventing them from ever aging out) and always drained `nr_to_scan`, guaranteeing the `-EAGAIN` requeue. Fix this in three steps: - Return `KEEP` instead of `TOUCH` when `expire_dir_lease` is `false`. If we are not going to reclaim the lease, leave it in place instead of churning the list and resetting its timestamp; the walk then terminates naturally (or via `STOP` at the first fresh lease). - Only return `-EAGAIN` from the first (dentry-lease) walk when something was actually freed. A full batch that frees nothing means retrying the same list immediately is futile; fall through to the dir-lease walk instead. - After both walks, bail out with success (0) when nothing was freed and there is no cap pressure (`count==0`). There is no reason to keep retrying when we are not over the cap limit and made no progress. Under real cap pressure (`count>0`) the reclaim path is unchanged and still retries via `-EAGAIN`. Without this patch, I saw 500 ceph_trim_dentries() calls per second on ou

Засегнати продукти

  • Linux Linux: 37c4efc1ddf98ba8b234d116d863a9464445901e преди f2f6daf8e99e15d636b1706bb4efd9a856195324; 37c4efc1ddf98ba8b234d116d863a9464445901e преди dd2e9824e5e7dba406005ff779a107f773175a76; 37c4efc1ddf98ba8b234d116d863a9464445901e преди 5a541eb401acb89d791da41189d7a79220164b93; 37c4efc1ddf98ba8b234d116d863a9464445901e преди 37d6edb2f03b29399a3a337fae78674de51e1695; 37c4efc1ddf98ba8b234d116d863a9464445901e преди 3d122b2feb1dd76bb5041bdea5e1e1b007d8d415; 37c4efc1ddf98ba8b234d116d863a9464445901e преди e7d7aa7b730178278109c41fa1b17b06873065d5
  • Linux Linux: 5.1; преди 5.1; 6.1.191 до 6.1.*; 6.6.160 до 6.6.*; 6.12.109 до 6.12.*; 6.18.50 до 6.18.*; 7.2.4 до 7.2.*; от 7.3 нататък

История

  • 11 септември 2026 Публикувано

Други уязвимости в Linux Linux

Първоизточници

CVE-2026-89647: Linux | freedomonline.bg