{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.85-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.18.14-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  quota: fix livelock between quotactl and freeze_super  When a filesystem is frozen, quotactl_block() enters a retry loop waiting for the filesystem to thaw. It acquires s_umount, checks the freeze state, drops s_umount and uses sb_start_write() - sb_end_write() pair to wait for the unfreeze.  However, this retry loop can trigger a livelock issue, specifically on kernels with preemption disabled.  The mechanism is as follows: 1. freeze_super() sets SB_FREEZE_WRITE and calls sb_wait_write(). 2. sb_wait_write() calls percpu_down_write(), which initiates    synchronize_rcu(). 3. Simultaneously, quotactl_block() spins in its retry loop, immediately    executing the sb_start_write() - sb_end_write() pair. 4. Because the kernel is non-preemptible and the loop contains no    scheduling points, quotactl_block() never yields the CPU. This    prevents that CPU from reaching an RCU quiescent state. 5. synchronize_rcu() in the freezer thread waits indefinitely for the    quotactl_block() CPU to report a quiescent state. 6. quotactl_block() spins indefinitely waiting for the freezer to    advance, which it cannot do as it is blocked on the RCU sync.  This results in a hang of the freezer process and 100% CPU usage by the quota process.  While this can occur intermittently on multi-core systems, it is reliably reproducing on a node with the following script, running both the freezer and the quota toggle on the same CPU:    # mkfs.ext4 -O quota /dev/sda 2g \u0026\u0026 mkdir a_mount   # mount /dev/sda -o quota,usrquota,grpquota a_mount   # taskset -c 3 bash -c \"while true; do xfs_freeze -f a_mount; \\     xfs_freeze -u a_mount; done\" \u0026   # taskset -c 3 bash -c \"while true; do quotaon a_mount; \\     quotaoff a_mount; done\" \u0026  Adding cond_resched() to the retry loop fixes the issue. It acts as an RCU quiescent state, allowing synchronize_rcu() in percpu_down_write() to complete.",
  "id": "DEBIAN-CVE-2026-45895",
  "modified": "2026-06-26T09:48:27.061523806Z",
  "published": "2026-05-27T14:17:03.733Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-45895"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-45895"
  ]
}