{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2023-54067",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2023-54067"
  ],
  "published": "2025-12-24T12:27:01Z",
  "summary": "btrfs: fix race when deleting free space root from the dirty cow roots list",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix race when deleting free space root from the dirty cow roots list\n\nWhen deleting the free space tree we are deleting the free space root\nfrom the list fs_info->dirty_cowonly_roots without taking the lock that\nprotects it, which is struct btrfs_fs_info::trans_lock.\nThis unsynchronized list manipulation may cause chaos if there's another\nconcurrent manipulation of this list, such as when adding a root to it\nwith ctree.c:add_root_to_dirty_list().\n\nThis can result in all sorts of weird failures caused by a race, such as\nthe following crash:\n\n  [337571.278245] general protection fault, probably for non-canonical address 0xdead000000000108: 0000 [#1] PREEMPT SMP PTI\n  [337571.278933] CPU: 1 PID: 115447 Comm: btrfs Tainted: G        W          6.4.0-rc6-btrfs-next-134+ #1\n  [337571.279153] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014\n  [337571.279572] RIP: 0010:commit_cowonly_roots+0x11f/0x250 [btrfs]\n  [337571.279928] Code: 85 38 06 00 (...)\n  [337571.280363] RSP: 0018:ffff9f63446efba0 EFLAGS: 00010206\n  [337571.280582] RAX: ffff942d98ec2638 RBX: ffff9430b82b4c30 RCX: 0000000449e1c000\n  [337571.280798] RDX: dead000000000100 RSI: ffff9430021e4900 RDI: 0000000000036070\n  [337571.281015] RBP: ffff942d98ec2000 R08: ffff942d98ec2000 R09: 000000000000015b\n  [337571.281254] R10: 0000000000000009 R11: 0000000000000001 R12: ffff942fe8fbf600\n  [337571.281476] R13: ffff942dabe23040 R14: ffff942dabe20800 R15: ffff942d92cf3b48\n  [337571.281723] FS:  00007f478adb7340(0000) GS:ffff94349fa40000(0000) knlGS:0000000000000000\n  [337571.281950] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  [337571.282184] CR2: 00007f478ab9a3d5 CR3: 000000001e02c001 CR4: 0000000000370ee0\n  [337571.282416] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n  [337571.282647] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n  [337571.282874] Call Trace:\n  [337571.283101]  <TASK>\n  [337571.283327]  ? __die_body+0x1b/0x60\n  [337571.283570]  ? die_addr+0x39/0x60\n  [337571.283796]  ? exc_general_protection+0x22e/0x430\n  [337571.284022]  ? asm_exc_general_protection+0x22/0x30\n  [337571.284251]  ? commit_cowonly_roots+0x11f/0x250 [btrfs]\n  [337571.284531]  btrfs_commit_transaction+0x42e/0xf90 [btrfs]\n  [337571.284803]  ? _raw_spin_unlock+0x15/0x30\n  [337571.285031]  ? release_extent_buffer+0x103/0x130 [btrfs]\n  [337571.285305]  reset_balance_state+0x152/0x1b0 [btrfs]\n  [337571.285578]  btrfs_balance+0xa50/0x11e0 [btrfs]\n  [337571.285864]  ? __kmem_cache_alloc_node+0x14a/0x410\n  [337571.286086]  btrfs_ioctl+0x249a/0x3320 [btrfs]\n  [337571.286358]  ? mod_objcg_state+0xd2/0x360\n  [337571.286577]  ? refill_obj_stock+0xb0/0x160\n  [337571.286798]  ? seq_release+0x25/0x30\n  [337571.287016]  ? __rseq_handle_notify_resume+0x3ba/0x4b0\n  [337571.287235]  ? percpu_counter_add_batch+0x2e/0xa0\n  [337571.287455]  ? __x64_sys_ioctl+0x88/0xc0\n  [337571.287675]  __x64_sys_ioctl+0x88/0xc0\n  [337571.287901]  do_syscall_64+0x38/0x90\n  [337571.288126]  entry_SYSCALL_64_after_hwframe+0x72/0xdc\n  [337571.288352] RIP: 0033:0x7f478aaffe9b\n\nSo fix this by locking struct btrfs_fs_info::trans_lock before deleting\nthe free space root from that list.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.21-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v6",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v7",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v7l",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v8",
            "binary_version": "1:6.1.21-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.21-1+rpt1": {
            "linux_commit": "0afb5e98488aed7017b9bf321b575d0177feb7ed",
            "upstream_version": "6.1.21",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.39"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2023-54067"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/6f1c81886b0b56cb88b311e5d2f203625474d892"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8ce9139aea5e60a247bde5af804312f54975f443"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/babebf023e661b90b1c78b2baa384fb03a226879"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T11:24:39Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The vulnerable code is reached only through mount(2)/remount of a local btrfs filesystem (`open_ctree()` or `btrfs_remount()` \u2192 `btrfs_start_pre_rw_mount()`), i.e. a local block device or image file. No network or remote peer data is involved.\nAC:L - On every affected kernel a plain default mount of an image whose superblock has FREE_SPACE_TREE set with FREE_SPACE_TREE_VALID clear unconditionally enters the unlocked `list_del`, and the attacker shapes the image so the cleaner/transaction kthreads are concurrently COWing cow-only roots during that window; the mount can be repeated until the race is won.\nPR:N - The attacker needs no privileges or account on the target \u2014 they only supply the crafted btrfs image (removable media, disk image, or file mounted by an automounter); the privileged mount is performed by the victim, not by the attacker.\nUI:R - A user or automounter must mount (or remount ro\u2192rw) the attacker-supplied btrfs filesystem for the vulnerable `btrfs_clear_free_space_tree()`/`btrfs_delete_free_space_tree()` path to execute.\nS:U - The corrupted `fs_info->dirty_cowonly_roots` list and the freed `struct btrfs_root` live entirely in the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The corruption leaves a `btrfs_root` that has just been released by `btrfs_put_root()` reachable from the commit list, so subsequent commits read a freed slab object whose contents the attacker can groom, yielding kernel memory disclosure.\nI:H - Unsynchronized `list_del`/`list_move` on a shared list writes attacker-influenced pointers through corrupted `next`/`prev` fields and then writes into the freed root object, giving a memory-corruption/write primitive usable for control-flow hijacking.\nA:H - The documented outcome is a general protection fault on LIST_POISON in `commit_cowonly_roots()` during `btrfs_commit_transaction()`, i.e. a kernel oops/panic taking the filesystem and system down."
    }
  }
}