{
  "affected": [],
  "aliases": [
    "CVE-2024-26905"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-04-17T11:15:11Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix data races when accessing the reserved amount of block reserves\n\nAt space_info.c we have several places where we access the -\u003ereserved\nfield of a block reserve without taking the block reserve\u0027s spinlock\nfirst, which makes KCSAN warn about a data race since that field is\nalways updated while holding the spinlock.\n\nThe reports from KCSAN are like the following:\n\n  [117.193526] BUG: KCSAN: data-race in btrfs_block_rsv_release [btrfs] / need_preemptive_reclaim [btrfs]\n\n  [117.195148] read to 0x000000017f587190 of 8 bytes by task 6303 on cpu 3:\n  [117.195172]  need_preemptive_reclaim+0x222/0x2f0 [btrfs]\n  [117.195992]  __reserve_bytes+0xbb0/0xdc8 [btrfs]\n  [117.196807]  btrfs_reserve_metadata_bytes+0x4c/0x120 [btrfs]\n  [117.197620]  btrfs_block_rsv_add+0x78/0xa8 [btrfs]\n  [117.198434]  btrfs_delayed_update_inode+0x154/0x368 [btrfs]\n  [117.199300]  btrfs_update_inode+0x108/0x1c8 [btrfs]\n  [117.200122]  btrfs_dirty_inode+0xb4/0x140 [btrfs]\n  [117.200937]  btrfs_update_time+0x8c/0xb0 [btrfs]\n  [117.201754]  touch_atime+0x16c/0x1e0\n  [117.201789]  filemap_read+0x674/0x728\n  [117.201823]  btrfs_file_read_iter+0xf8/0x410 [btrfs]\n  [117.202653]  vfs_read+0x2b6/0x498\n  [117.203454]  ksys_read+0xa2/0x150\n  [117.203473]  __s390x_sys_read+0x68/0x88\n  [117.203495]  do_syscall+0x1c6/0x210\n  [117.203517]  __do_syscall+0xc8/0xf0\n  [117.203539]  system_call+0x70/0x98\n\n  [117.203579] write to 0x000000017f587190 of 8 bytes by task 11 on cpu 0:\n  [117.203604]  btrfs_block_rsv_release+0x2e8/0x578 [btrfs]\n  [117.204432]  btrfs_delayed_inode_release_metadata+0x7c/0x1d0 [btrfs]\n  [117.205259]  __btrfs_update_delayed_inode+0x37c/0x5e0 [btrfs]\n  [117.206093]  btrfs_async_run_delayed_root+0x356/0x498 [btrfs]\n  [117.206917]  btrfs_work_helper+0x160/0x7a0 [btrfs]\n  [117.207738]  process_one_work+0x3b6/0x838\n  [117.207768]  worker_thread+0x75e/0xb10\n  [117.207797]  kthread+0x21a/0x230\n  [117.207830]  __ret_from_fork+0x6c/0xb8\n  [117.207861]  ret_from_fork+0xa/0x30\n\nSo add a helper to get the reserved amount of a block reserve while\nholding the lock. The value may be not be up to date anymore when used by\nneed_preemptive_reclaim() and btrfs_preempt_reclaim_metadata_space(), but\nthat\u0027s ok since the worst it can do is cause more reclaim work do be done\nsooner rather than later. Reading the field while holding the lock instead\nof using the data_race() annotation is used in order to prevent load\ntearing.",
  "id": "GHSA-x6g6-grg7-wwcp",
  "modified": "2024-04-17T12:32:05Z",
  "published": "2024-04-17T12:32:05Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26905"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/82220b1835baaebf4ae2e490f56353a341a09bd2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/995e91c9556c8fc6028b474145a36e947d1eb6b6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c44542093525699a30c307dae1ea5a1b03b3302f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e06cc89475eddc1f3a7a4d471524256152c68166"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}