{"id":"CVE-2025-22123","summary":"f2fs: fix to avoid accessing uninitialized curseg","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to avoid accessing uninitialized curseg\n\nsyzbot reports a f2fs bug as below:\n\nF2FS-fs (loop3): Stopped filesystem due to reason: 7\nkworker/u8:7: attempt to access beyond end of device\nBUG: unable to handle page fault for address: ffffed1604ea3dfa\nRIP: 0010:get_ckpt_valid_blocks fs/f2fs/segment.h:361 [inline]\nRIP: 0010:has_curseg_enough_space fs/f2fs/segment.h:570 [inline]\nRIP: 0010:__get_secs_required fs/f2fs/segment.h:620 [inline]\nRIP: 0010:has_not_enough_free_secs fs/f2fs/segment.h:633 [inline]\nRIP: 0010:has_enough_free_secs+0x575/0x1660 fs/f2fs/segment.h:649\n \u003cTASK\u003e\n f2fs_is_checkpoint_ready fs/f2fs/segment.h:671 [inline]\n f2fs_write_inode+0x425/0x540 fs/f2fs/inode.c:791\n write_inode fs/fs-writeback.c:1525 [inline]\n __writeback_single_inode+0x708/0x10d0 fs/fs-writeback.c:1745\n writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976\n wb_writeback+0x413/0xb80 fs/fs-writeback.c:2156\n wb_do_writeback fs/fs-writeback.c:2303 [inline]\n wb_workfn+0x410/0x1080 fs/fs-writeback.c:2343\n process_one_work kernel/workqueue.c:3236 [inline]\n process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317\n worker_thread+0x870/0xd30 kernel/workqueue.c:3398\n kthread+0x7a9/0x920 kernel/kthread.c:464\n ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244\n\nCommit 8b10d3653735 (\"f2fs: introduce FAULT_NO_SEGMENT\") allows to trigger\nno free segment fault in allocator, then it will update curseg-\u003esegno to\nNULL_SEGNO, though, CP_ERROR_FLAG has been set, f2fs_write_inode() missed\nto check the flag, and access invalid curseg-\u003esegno directly in below call\npath, then resulting in panic:\n\n- f2fs_write_inode\n - f2fs_is_checkpoint_ready\n  - has_enough_free_secs\n   - has_not_enough_free_secs\n    - __get_secs_required\n     - has_curseg_enough_space\n      - get_ckpt_valid_blocks\n      : access invalid curseg-\u003esegno\n\nTo avoid this issue, let's:\n- check CP_ERROR_FLAG flag in prior to f2fs_is_checkpoint_ready() in\nf2fs_write_inode().\n- in has_curseg_enough_space(), save curseg-\u003esegno into a temp variable,\nand verify its validation before use.","modified":"2026-03-20T12:41:20.655180Z","published":"2025-04-16T14:13:07.213Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/22xxx/CVE-2025-22123.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/7f90e5d423cd2d4c74b2abb527872f335108637f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/986c50f6bca109c6cf362b4e2babcb85aba958f6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bf49527089ec1ba894c6e587affabbfb2329f52e"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/22xxx/CVE-2025-22123.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-22123"},{"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":"8b10d3653735e117bc1954ade80d75ad7b46b801"},{"fixed":"bf49527089ec1ba894c6e587affabbfb2329f52e"},{"fixed":"7f90e5d423cd2d4c74b2abb527872f335108637f"},{"fixed":"986c50f6bca109c6cf362b4e2babcb85aba958f6"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-22123.json"}}],"schema_version":"1.7.5"}