CVE-2026-98818

Что произошло

In the Linux kernel, the following vulnerability has been resolved: mm/slab: do not wake up kswapd in __kfree_rcu_sheaf() Since kfree_rcu() can be called under pi_lock (a raw spinlock in the scheduler), kfree_rcu() itself should never allocate memory with __GFP_KSWAPD_RECLAIM as waking up kswapd ends up acquiring pi_lock, which leads to a deadlock. Reproducing the issue even intentionally was not straightforward. The set_cpus_allowed_force() path that is called under pi_lock is exercised very rarely, and competing tasks that allocate memory will most likely wake kswapd up. Therefore the existence of the deadlock was verified with a modified kernel that has a lockdep map for waking up kswapd: ====================================================== WARNING: possible circular locking dependency detected 7.2.0-rc1-slab-for-next+ #10 Not tainted ------------------------------------------------------ git/6660 is trying to acquire lock: ffff8e524533c550 (&p->pi_lock){-.-.}-{2:2}, at: _raw_spin_lock_irqsave+0x12/0x20 but task is already holding lock: ffff8e57bffff1a0 (&pgdat->kswapd_wait){....}-{3:3}, at: _raw_spin_lock_irqsave+0x12/0x20 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&pgdat->kswapd_wait){....}-{3:3}: __lock_acquire+0x5a4/0xc50 lock_acquire.part.0+0xb7/0x240 lock_acquire+0x70/0x170 __raw_spin_lock_irqsave+0x44/0x80 _raw_spin_lock_irqsave+0x12/0x20 __wake_up_common_lock+0x31/0xa0 __wake_up+0x20/0x40 kswapd_wakeup_wake+0x7e/0x110 wakeup_kswapd+0x295/0x320 wake_all_kswapds+0xac/0x1a0 __alloc_pages_slowpath.constprop.0+0x282/0xf80 __alloc_frozen_pages_noprof+0x32a/0x360 alloc_slab_page+0x2e/0x160 allocate_slab+0x82/0x420 new_slab+0x52/0xb0 refill_objects+0x13d/0x190 refill_sheaf+0x5d/0xd0 __pcs_replace_empty_main+0x230/0xb10 [...] -> #1 (kswapd_wakeup){-.-.}-{0:0}: __lock_acquire+0x5a4/0xc50 lock_sync.part.0+0x75/0x100 lock_sync+0x36/0x70 might_wakeup_kswapd+0x61/0xa0 __kfree_rcu_sheaf+0x33/0xd90 kvfree_call_rcu+0x1d4/0x3b0 set_cpus_allowed_force+0x163/0x220 cpuset_cpus_allowed_fallback+0x18b/0x240 select_fallback_rq+0x1e6/0x250 [...] -> #0 (&p->pi_lock){-.-.}-{2:2}: check_prev_add+0xe6/0xe00 validate_chain+0x51e/0x6e0 __lock_acquire+0x5a4/0xc50 lock_acquire.part.0+0xb7/0x240 lock_acquire+0x70/0x170 __raw_spin_lock_irqsave+0x44/0x80 _raw_spin_lock_irqsave+0x12/0x20 try_to_wake_up+0x77/0xa90 default_wake_function+0x27/0x60 autoremove_wake_function+0x23/0xb0 __wake_up_common+0xb8/0x170 __wake_up_common_lock+0x51/0xa0 __wake_up+0x20/0x40 kswapd_wakeup_wake+0x7e/0x110 wakeup_kswapd+0x295/0x320 wake_all_kswapds+0xac/0x1a0 __alloc_pages_slowpath.constprop.0+0x282/0xf80 __alloc_frozen_pages_noprof+0x32a/0x360 alloc_slab_page+0x2e/0x160 allocate_slab+0x82/0x420 new_slab+0x52/0xb0 refill_objects+0x13d/0x190 refill_sheaf+0x5d/0xd0 __pcs_replace_empty_main+0x230/0xb10 [...] other info that might help us debug this: Chain exists of: &p->pi_lock --> kswapd_wakeup --> &pgdat->kswapd_wait Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&pgdat->kswapd_wait); lock(kswapd_wakeup); lock(&pgdat->kswapd_wait); lock(&p->pi_lock); *** DEADLOCK *** 3 locks held by git/6660: #0: ffff8e519f0e9e20 (&type->i_mutex_dir_key#6){++++}-{4:4}, at: lookup_slow+0x2d/0x60 #1: ffffffff8a31c460 (kswapd_wakeup){-.-.}- ---truncated---

Что делать

dpkg-query -W -f='${Package}	${Version}\n'

rpm -qa --qf '%{NAME}\t%{VERSION}-%{RELEASE}\n'

Get-HotFix | Select-Object HotFixID, InstalledOn

Продукты и затронутые версии

{
  "status": "affected",
  "version": "ec66e0d599520ab414db745544e25d80d0ac5054",
  "lessThan": "46545c86b54ffb969b6e3662942b4a6191619eaa",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "ec66e0d599520ab414db745544e25d80d0ac5054",
  "lessThan": "af2fb3ee6679b517e2fdbd3ba16ec276a8b74312",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "6.18"
}

{
  "status": "unaffected",
  "version": "0",
  "lessThan": "6.18",
  "versionType": "semver"
}

{
  "status": "unaffected",
  "version": "7.2.10",
  "versionType": "semver",
  "lessThanOrEqual": "7.2.*"
}

{
  "status": "unaffected",
  "version": "7.3",
  "versionType": "original_commit_for_fix",
  "lessThanOrEqual": "*"
}

CVSS: оценки и векторы

Оценка CVSS отсутствует.

Источники и ссылки

{
  "cwes": [],
  "epss": {
    "source": "epss",
    "received_at": "2026-11-02T21:15:49.063030+00:00"
  },
  "title": {
    "source": "cve",
    "received_at": "2026-10-28T20:13:06.598083+00:00"
  },
  "scores": [],
  "status": {
    "source": "cve",
    "received_at": "2026-10-28T20:13:06.598083+00:00"
  },
  "affected": [
    "cve"
  ],
  "published": {
    "source": "cve",
    "received_at": "2026-10-28T20:13:06.598083+00:00"
  },
  "solutions": [],
  "percentile": {
    "source": "epss",
    "received_at": "2026-11-02T21:15:49.063030+00:00"
  },
  "references": [
    "cve"
  ],
  "description": {
    "source": "cve",
    "received_at": "2026-10-28T20:13:06.598083+00:00"
  },
  "workarounds": [],
  "configurations": []
}

Хронология записи

1. Данные обновлены03.11.2026, 00:15
2. Данные обновлены02.11.2026, 00:13
3. Данные обновлены31.10.2026, 12:00
4. Данные обновлены29.10.2026, 12:47
5. Опубликована28.10.2026, 23:13

Личная заметка и статус

Другие CVE того же продукта