{"id":"CVE-2025-68772","summary":"f2fs: fix to avoid updating compression context during writeback","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to avoid updating compression context during writeback\n\nBai, Shuangpeng \u003csjb7183@psu.edu\u003e reported a bug as below:\n\nOops: divide error: 0000 [#1] SMP KASAN PTI\nCPU: 0 UID: 0 PID: 11441 Comm: syz.0.46 Not tainted 6.17.0 #1 PREEMPT(full)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014\nRIP: 0010:f2fs_all_cluster_page_ready+0x106/0x550 fs/f2fs/compress.c:857\nCall Trace:\n \u003cTASK\u003e\n f2fs_write_cache_pages fs/f2fs/data.c:3078 [inline]\n __f2fs_write_data_pages fs/f2fs/data.c:3290 [inline]\n f2fs_write_data_pages+0x1c19/0x3600 fs/f2fs/data.c:3317\n do_writepages+0x38e/0x640 mm/page-writeback.c:2634\n filemap_fdatawrite_wbc mm/filemap.c:386 [inline]\n __filemap_fdatawrite_range mm/filemap.c:419 [inline]\n file_write_and_wait_range+0x2ba/0x3e0 mm/filemap.c:794\n f2fs_do_sync_file+0x6e6/0x1b00 fs/f2fs/file.c:294\n generic_write_sync include/linux/fs.h:3043 [inline]\n f2fs_file_write_iter+0x76e/0x2700 fs/f2fs/file.c:5259\n new_sync_write fs/read_write.c:593 [inline]\n vfs_write+0x7e9/0xe00 fs/read_write.c:686\n ksys_write+0x19d/0x2d0 fs/read_write.c:738\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xf7/0x470 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nThe bug was triggered w/ below race condition:\n\nfsync\t\t\t\tsetattr\t\t\tioctl\n- f2fs_do_sync_file\n - file_write_and_wait_range\n  - f2fs_write_cache_pages\n  : inode is non-compressed\n  : cc.cluster_size =\n    F2FS_I(inode)-\u003ei_cluster_size = 0\n   - tag_pages_for_writeback\n\t\t\t\t- f2fs_setattr\n\t\t\t\t - truncate_setsize\n\t\t\t\t - f2fs_truncate\n\t\t\t\t\t\t\t- f2fs_fileattr_set\n\t\t\t\t\t\t\t - f2fs_setflags_common\n\t\t\t\t\t\t\t  - set_compress_context\n\t\t\t\t\t\t\t  : F2FS_I(inode)-\u003ei_cluster_size = 4\n\t\t\t\t\t\t\t  : set_inode_flag(inode, FI_COMPRESSED_FILE)\n   - f2fs_compressed_file\n   : return true\n   - f2fs_all_cluster_page_ready\n   : \"pgidx % cc-\u003ecluster_size\" trigger dividing 0 issue\n\nLet's change as below to fix this issue:\n- introduce a new atomic type variable .writeback in structure f2fs_inode_info\nto track the number of threads which calling f2fs_write_cache_pages().\n- use .i_sem lock to protect .writeback update.\n- check .writeback before update compression context in f2fs_setflags_common()\nto avoid race w/ -\u003ewritepages.","modified":"2026-03-20T12:46:28.603852Z","published":"2026-01-13T15:28:49.924Z","related":["MGASA-2026-0017","MGASA-2026-0018"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/68xxx/CVE-2025-68772.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0bf1a02494c7eb5bd43445de4c83c8592e02c4bf"},{"type":"WEB","url":"https://git.kernel.org/stable/c/0df713a9c082a474c8b0bcf670edc8e98461d5a0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/10b591e7fb7cdc8c1e53e9c000dc0ef7069aaa76"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ad26bfbc085c939b5dca77ff8c14798c06d151c4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bcd0086ee5a2e88c1224ff2ec1e4a43c83efe5a0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/68xxx/CVE-2025-68772.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-68772"},{"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":"4c8ff7095bef64fc47e996a938f7d57f9e077da3"},{"fixed":"ad26bfbc085c939b5dca77ff8c14798c06d151c4"},{"fixed":"bcd0086ee5a2e88c1224ff2ec1e4a43c83efe5a0"},{"fixed":"0bf1a02494c7eb5bd43445de4c83c8592e02c4bf"},{"fixed":"0df713a9c082a474c8b0bcf670edc8e98461d5a0"},{"fixed":"10b591e7fb7cdc8c1e53e9c000dc0ef7069aaa76"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-68772.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.6.0"},{"fixed":"6.1.160"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.120"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.64"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-68772.json"}}],"schema_version":"1.7.5"}