{"id":"CVE-2022-50067","summary":"btrfs: unset reloc control if transaction commit fails in prepare_to_relocate()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: unset reloc control if transaction commit fails in prepare_to_relocate()\n\nIn btrfs_relocate_block_group(), the rc is allocated.  Then\nbtrfs_relocate_block_group() calls\n\nrelocate_block_group()\n  prepare_to_relocate()\n    set_reloc_control()\n\nthat assigns rc to the variable fs_info-\u003ereloc_ctl. When\nprepare_to_relocate() returns, it calls\n\nbtrfs_commit_transaction()\n  btrfs_start_dirty_block_groups()\n    btrfs_alloc_path()\n      kmem_cache_zalloc()\n\nwhich may fail for example (or other errors could happen). When the\nfailure occurs, btrfs_relocate_block_group() detects the error and frees\nrc and doesn't set fs_info-\u003ereloc_ctl to NULL. After that, in\nbtrfs_init_reloc_root(), rc is retrieved from fs_info-\u003ereloc_ctl and\nthen used, which may cause a use-after-free bug.\n\nThis possible bug can be triggered by calling btrfs_ioctl_balance()\nbefore calling btrfs_ioctl_defrag().\n\nTo fix this possible bug, in prepare_to_relocate(), check if\nbtrfs_commit_transaction() fails. If the failure occurs,\nunset_reloc_control() is called to set fs_info-\u003ereloc_ctl to NULL.\n\nThe error log in our fault-injection testing is shown as follows:\n\n  [   58.751070] BUG: KASAN: use-after-free in btrfs_init_reloc_root+0x7ca/0x920 [btrfs]\n  ...\n  [   58.753577] Call Trace:\n  ...\n  [   58.755800]  kasan_report+0x45/0x60\n  [   58.756066]  btrfs_init_reloc_root+0x7ca/0x920 [btrfs]\n  [   58.757304]  record_root_in_trans+0x792/0xa10 [btrfs]\n  [   58.757748]  btrfs_record_root_in_trans+0x463/0x4f0 [btrfs]\n  [   58.758231]  start_transaction+0x896/0x2950 [btrfs]\n  [   58.758661]  btrfs_defrag_root+0x250/0xc00 [btrfs]\n  [   58.759083]  btrfs_ioctl_defrag+0x467/0xa00 [btrfs]\n  [   58.759513]  btrfs_ioctl+0x3c95/0x114e0 [btrfs]\n  ...\n  [   58.768510] Allocated by task 23683:\n  [   58.768777]  ____kasan_kmalloc+0xb5/0xf0\n  [   58.769069]  __kmalloc+0x227/0x3d0\n  [   58.769325]  alloc_reloc_control+0x10a/0x3d0 [btrfs]\n  [   58.769755]  btrfs_relocate_block_group+0x7aa/0x1e20 [btrfs]\n  [   58.770228]  btrfs_relocate_chunk+0xf1/0x760 [btrfs]\n  [   58.770655]  __btrfs_balance+0x1326/0x1f10 [btrfs]\n  [   58.771071]  btrfs_balance+0x3150/0x3d30 [btrfs]\n  [   58.771472]  btrfs_ioctl_balance+0xd84/0x1410 [btrfs]\n  [   58.771902]  btrfs_ioctl+0x4caa/0x114e0 [btrfs]\n  ...\n  [   58.773337] Freed by task 23683:\n  ...\n  [   58.774815]  kfree+0xda/0x2b0\n  [   58.775038]  free_reloc_control+0x1d6/0x220 [btrfs]\n  [   58.775465]  btrfs_relocate_block_group+0x115c/0x1e20 [btrfs]\n  [   58.775944]  btrfs_relocate_chunk+0xf1/0x760 [btrfs]\n  [   58.776369]  __btrfs_balance+0x1326/0x1f10 [btrfs]\n  [   58.776784]  btrfs_balance+0x3150/0x3d30 [btrfs]\n  [   58.777185]  btrfs_ioctl_balance+0xd84/0x1410 [btrfs]\n  [   58.777621]  btrfs_ioctl+0x4caa/0x114e0 [btrfs]\n  ...","modified":"2026-04-03T13:14:35.623355Z","published":"2025-06-18T11:02:13.127Z","related":["SUSE-SU-2025:02264-1","SUSE-SU-2025:02308-1","SUSE-SU-2025:02312-1","SUSE-SU-2025:02320-1","SUSE-SU-2025:02321-1","SUSE-SU-2025:02322-1","SUSE-SU-2025:02334-1","SUSE-SU-2025:02537-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50067.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/5d741afed0bac206640cc64d77b97853283cf719"},{"type":"WEB","url":"https://git.kernel.org/stable/c/78f8c2370e3d33e35f23bdc648653d779aeacb6e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/85f02d6c856b9f3a0acf5219de6e32f58b9778eb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8e546674031fc1576da501e27a8fd165222e5a37"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b60e862e133f646f19023ece1d476d630a660de1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/dcb11fe0a0a9cca2b7425191b9bf30dc29f2ad0f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ff0e8ed8dfb584575cffc1561f17a1d094e8565b"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50067.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-50067"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"1a5353475df8fcaf200fecc9e961a3900d15e891"},{"fixed":"ff0e8ed8dfb584575cffc1561f17a1d094e8565b"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"499d29bf151951399367ba83645abfdb429a3af9"},{"fixed":"dcb11fe0a0a9cca2b7425191b9bf30dc29f2ad0f"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4223d91ca1b5bf3928e5722c3c6b3fdb49250ab3"},{"fixed":"8e546674031fc1576da501e27a8fd165222e5a37"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6f371623f315c26100e603c2e8837cdbe130f9e0"},{"fixed":"b60e862e133f646f19023ece1d476d630a660de1"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"fb686c6824dd6294ca772b92424b8fba666e7d00"},{"fixed":"78f8c2370e3d33e35f23bdc648653d779aeacb6e"},{"fixed":"5d741afed0bac206640cc64d77b97853283cf719"},{"fixed":"85f02d6c856b9f3a0acf5219de6e32f58b9778eb"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2022-50067.json"}}],"schema_version":"1.7.5"}