{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "descriptions": [
            {
               "lang": "en",
               "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix data race at btrfs_use_block_rsv() when accessing block reserve\n\nAt btrfs_use_block_rsv() we read the size of a block reserve without\nlocking its spinlock, which makes KCSAN complain because the size of a\nblock reserve is always updated while holding its spinlock. The report\nfrom KCSAN is the following:\n\n  [653.313148] BUG: KCSAN: data-race in btrfs_update_delayed_refs_rsv [btrfs] / btrfs_use_block_rsv [btrfs]\n\n  [653.314755] read to 0x000000017f5871b8 of 8 bytes by task 7519 on cpu 0:\n  [653.314779]  btrfs_use_block_rsv+0xe4/0x2f8 [btrfs]\n  [653.315606]  btrfs_alloc_tree_block+0xdc/0x998 [btrfs]\n  [653.316421]  btrfs_force_cow_block+0x220/0xe38 [btrfs]\n  [653.317242]  btrfs_cow_block+0x1ac/0x568 [btrfs]\n  [653.318060]  btrfs_search_slot+0xda2/0x19b8 [btrfs]\n  [653.318879]  btrfs_del_csums+0x1dc/0x798 [btrfs]\n  [653.319702]  __btrfs_free_extent.isra.0+0xc24/0x2028 [btrfs]\n  [653.320538]  __btrfs_run_delayed_refs+0xd3c/0x2390 [btrfs]\n  [653.321340]  btrfs_run_delayed_refs+0xae/0x290 [btrfs]\n  [653.322140]  flush_space+0x5e4/0x718 [btrfs]\n  [653.322958]  btrfs_preempt_reclaim_metadata_space+0x102/0x2f8 [btrfs]\n  [653.323781]  process_one_work+0x3b6/0x838\n  [653.323800]  worker_thread+0x75e/0xb10\n  [653.323817]  kthread+0x21a/0x230\n  [653.323836]  __ret_from_fork+0x6c/0xb8\n  [653.323855]  ret_from_fork+0xa/0x30\n\n  [653.323887] write to 0x000000017f5871b8 of 8 bytes by task 576 on cpu 3:\n  [653.323906]  btrfs_update_delayed_refs_rsv+0x1a4/0x250 [btrfs]\n  [653.324699]  btrfs_add_delayed_data_ref+0x468/0x6d8 [btrfs]\n  [653.325494]  btrfs_free_extent+0x76/0x120 [btrfs]\n  [653.326280]  __btrfs_mod_ref+0x6a8/0x6b8 [btrfs]\n  [653.327064]  btrfs_dec_ref+0x50/0x70 [btrfs]\n  [653.327849]  walk_up_proc+0x236/0xa50 [btrfs]\n  [653.328633]  walk_up_tree+0x21c/0x448 [btrfs]\n  [653.329418]  btrfs_drop_snapshot+0x802/0x1328 [btrfs]\n  [653.330205]  btrfs_clean_one_deleted_snapshot+0x184/0x238 [btrfs]\n  [653.330995]  cleaner_kthread+0x2b0/0x2f0 [btrfs]\n  [653.331781]  kthread+0x21a/0x230\n  [653.331800]  __ret_from_fork+0x6c/0xb8\n  [653.331818]  ret_from_fork+0xa/0x30\n\nSo add a helper to get the size of a block reserve while holding the lock.\nReading the field while holding the lock instead of using the data_race()\nannotation is used in order to prevent load tearing."
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "versions": [
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "2daa2a8e895e",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "ab1be3f1aa77",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "f6d4d29a1265",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "7e9422d35d57",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "1da177e4c3f4",
                     "lessThan": "c7bb26b847e5",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "versions": [
                  {
                     "version": "5.4.273",
                     "lessThanOrEqual": "5.4.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.1.83",
                     "lessThanOrEqual": "6.1.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.6.23",
                     "lessThanOrEqual": "6.6.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.7.11",
                     "lessThanOrEqual": "6.7.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.8",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/2daa2a8e895e6dc2395f8628c011bcf1e019040d"
            },
            {
               "url": "https://git.kernel.org/stable/c/ab1be3f1aa7799f99155488c28eacaef65eb68fb"
            },
            {
               "url": "https://git.kernel.org/stable/c/f6d4d29a12655b42a13cec038c2902bb7efc50ed"
            },
            {
               "url": "https://git.kernel.org/stable/c/7e9422d35d574b646269ca46010a835ca074b310"
            },
            {
               "url": "https://git.kernel.org/stable/c/c7bb26b847e5b97814f522686068c5628e2b3646"
            }
         ],
         "title": "btrfs: fix data race at btrfs_use_block_rsv() when accessing block reserve",
         "x_generator": {
            "engine": "bippy-d175d3acf727"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2024-26904",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}