{"id":"CVE-2023-53447","summary":"f2fs: don't reset unchangable mount option in f2fs_remount()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: don't reset unchangable mount option in f2fs_remount()\n\nsyzbot reports a bug as below:\n\ngeneral protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] PREEMPT SMP KASAN\nRIP: 0010:__lock_acquire+0x69/0x2000 kernel/locking/lockdep.c:4942\nCall Trace:\n lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5691\n __raw_write_lock include/linux/rwlock_api_smp.h:209 [inline]\n _raw_write_lock+0x2e/0x40 kernel/locking/spinlock.c:300\n __drop_extent_tree+0x3ac/0x660 fs/f2fs/extent_cache.c:1100\n f2fs_drop_extent_tree+0x17/0x30 fs/f2fs/extent_cache.c:1116\n f2fs_insert_range+0x2d5/0x3c0 fs/f2fs/file.c:1664\n f2fs_fallocate+0x4e4/0x6d0 fs/f2fs/file.c:1838\n vfs_fallocate+0x54b/0x6b0 fs/open.c:324\n ksys_fallocate fs/open.c:347 [inline]\n __do_sys_fallocate fs/open.c:355 [inline]\n __se_sys_fallocate fs/open.c:353 [inline]\n __x64_sys_fallocate+0xbd/0x100 fs/open.c:353\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nThe root cause is race condition as below:\n- since it tries to remount rw filesystem, so that do_remount won't\ncall sb_prepare_remount_readonly to block fallocate, there may be race\ncondition in between remount and fallocate.\n- in f2fs_remount(), default_options() will reset mount option to default\none, and then update it based on result of parse_options(), so there is\na hole which race condition can happen.\n\nThread A\t\t\tThread B\n- f2fs_fill_super\n - parse_options\n  - clear_opt(READ_EXTENT_CACHE)\n\n- f2fs_remount\n - default_options\n  - set_opt(READ_EXTENT_CACHE)\n\t\t\t\t- f2fs_fallocate\n\t\t\t\t - f2fs_insert_range\n\t\t\t\t  - f2fs_drop_extent_tree\n\t\t\t\t   - __drop_extent_tree\n\t\t\t\t    - __may_extent_tree\n\t\t\t\t     - test_opt(READ_EXTENT_CACHE) return true\n\t\t\t\t    - write_lock(&et-\u003elock) access NULL pointer\n - parse_options\n  - clear_opt(READ_EXTENT_CACHE)","modified":"2026-04-02T09:44:13.759181Z","published":"2025-09-18T16:04:22.649Z","related":["SUSE-SU-2025:03600-1","SUSE-SU-2025:03634-1","SUSE-SU-2025:20851-1","SUSE-SU-2025:20861-1","SUSE-SU-2025:20870-1","SUSE-SU-2025:20898-1","SUSE-SU-2025:3751-1","SUSE-SU-2025:4057-1","SUSE-SU-2025:4132-1","SUSE-SU-2025:4141-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53447.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/115557cc226a927924f2d7d1980ccbf6e3b3bb36"},{"type":"WEB","url":"https://git.kernel.org/stable/c/458c15dfbce62c35fefd9ca637b20a051309c9f1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53447.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-53447"},{"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":"98e4da8ca301e062d79ae168c67e56f3c3de3ce4"},{"fixed":"115557cc226a927924f2d7d1980ccbf6e3b3bb36"},{"fixed":"458c15dfbce62c35fefd9ca637b20a051309c9f1"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53447.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}