{
  "cveId": "CVE-2026-64100",
  "url": "https://patchblox.com/security/cve/CVE-2026-64100",
  "summary": "CVE-2026-64100 is fixed in linux on 1 platform by DEBIAN-CVE-2026-64100 (version 7.0.12-1), released July 20, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  drm/msm: Fix shrinker deadlock  With PROVE_LOCKI...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  drm/msm: Fix shrinker deadlock  With PROVE_LOCKING on an Snapdragon X1 and VM reclaim pressure, we see:     ======================================================    WARNING: possible circular locking dependency detected    7.0.0-debug\u002B #43 Tainted: G        W    ------------------------------------------------------    kswapd0/82 is trying to acquire lock:    ffff800080ec3870 (reservation_ww_class_acquire){\u002B.\u002B.}-{0:0}, at: msm_gem_shrinker_scan\u002B0x17c/0x400 [msm]     but task is already holding lock:    ffffc31709b263b8 (fs_reclaim){\u002B.\u002B.}-{0:0}, at: balance_pgdat\u002B0x88/0x988     which lock already depends on the new lock.     the existing dependency chain (in reverse order) is:     -\u003E #2 (fs_reclaim){\u002B.\u002B.}-{0:0}:           __lock_acquire\u002B0x4d0/0xad0           lock_acquire.part.0\u002B0xc4/0x248           lock_acquire\u002B0x8c/0x248           fs_reclaim_acquire\u002B0xd0/0xf0           dma_resv_lockdep\u002B0x224/0x348           do_one_initcall\u002B0x84/0x5d0           do_initcalls\u002B0x194/0x1d8           kernel_init_freeable\u002B0x128/0x180           kernel_init\u002B0x2c/0x160           ret_from_fork\u002B0x10/0x20     -\u003E #1 (reservation_ww_class_mutex){\u002B.\u002B.}-{4:4}:           __lock_acquire\u002B0x4d0/0xad0           lock_acquire.part.0\u002B0xc4/0x248           lock_acquire\u002B0x8c/0x248           dma_resv_lockdep\u002B0x1a8/0x348           do_one_initcall\u002B0x84/0x5d0           do_initcalls\u002B0x194/0x1d8           kernel_init_freeable\u002B0x128/0x180           kernel_init\u002B0x2c/0x160           ret_from_fork\u002B0x10/0x20     -\u003E #0 (reservation_ww_class_acquire){\u002B.\u002B.}-{0:0}:           check_prev_add\u002B0x114/0x790           validate_chain\u002B0x594/0x6f0           __lock_acquire\u002B0x4d0/0xad0           lock_acquire.part.0\u002B0xc4/0x248           lock_acquire\u002B0x8c/0x248           drm_gem_lru_scan\u002B0x1ac/0x440           msm_gem_shrinker_scan\u002B0x17c/0x400 [msm]           do_shrink_slab\u002B0x150/0x4a0           shrink_slab\u002B0x144/0x460           shrink_one\u002B0x9c/0x1b0           shrink_many\u002B0x27c/0x5c0           shrink_node\u002B0x344/0x550           balance_pgdat\u002B0x2c0/0x988           kswapd\u002B0x11c/0x318           kthread\u002B0x10c/0x128           ret_from_fork\u002B0x10/0x20     other info that might help us debug this:    Chain exists of:      reservation_ww_class_acquire --\u003E reservation_ww_class_mutex --\u003E fs_reclaim     Possible unsafe locking scenario:           CPU0                    CPU1           ----                    ----      lock(fs_reclaim);                                   lock(reservation_ww_class_mutex);                                   lock(fs_reclaim);      lock(reservation_ww_class_acquire);      *** DEADLOCK ***    1 lock held by kswapd0/82:     #0: ffffc31709b263b8 (fs_reclaim){\u002B.\u002B.}-{0:0}, at: balance_pgdat\u002B0x88/0x988     stack backtrace:    CPU: 4 UID: 0 PID: 82 Comm: kswapd0 Tainted: G        W           7.0.0-debug\u002B #43 PREEMPT(full)    Tainted: [W]=WARN    Hardware name: LENOVO 21BX0016US/21BX0016US, BIOS N3HET94W (1.66 ) 09/15/2025    Call trace:     show_stack\u002B0x20/0x40 (C)     dump_stack_lvl\u002B0x9c/0xd0     dump_stack\u002B0x18/0x30     print_circular_bug\u002B0x114/0x120     check_noncircular\u002B0x178/0x198     check_prev_add\u002B0x114/0x790     validate_chain\u002B0x594/0x6f0     __lock_acquire\u002B0x4d0/0xad0     lock_acquire.part.0\u002B0xc4/0x248     lock_acquire\u002B0x8c/0x248     drm_gem_lru_scan\u002B0x1ac/0x440     msm_gem_shrinker_scan\u002B0x17c/0x400 [msm]     do_shrink_slab\u002B0x150/0x4a0     shrink_slab\u002B0x144/0x460     shrink_one\u002B0x9c/0x1b0     shrink_many\u002B0x27c/0x5c0     shrink_node\u002B0x344/0x550     balance_pgdat\u002B0x2c0/0x988     kswapd\u002B0x11c/0x318     kthread\u002B0x10c/0x128     ret_from_fork\u002B0x10/0x20  kswapd0 holding fs_reclaim calls the MSM shrinker, which calls dma_resv_lock. This in turn acquires fs_reclaim.  Fix this deadlock by using dma_resv_trylock() instead, dropping the subsequently unused passed wait-wound lock \u0027ticket\u0027.  Patchwork: https://patchwork.freedesktop.org/patch/723564/ [rob: fixup compile errors, replace lockdep splat with somethin ---truncated---",
  "published": "2026-07-19T16:17:51Z",
  "severity": "medium",
  "cvss": 5.5,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.00124,
  "epssPercentile": 0.02118,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.0.12-1",
      "fix": "DEBIAN-CVE-2026-64100",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-64100",
      "released": "2026-07-20T12:58:36Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T06:59:42Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}