{"cve":"CVE-2025-68772","nvd":{"published":"2026-01-13T16:15:56.707","modified":"2026-06-17T09:59:33.720","status":"Deferred","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to avoid updating compression context during writeback\n\nBai, Shuangpeng <sjb7183@psu.edu> 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 <TASK>\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)->i_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)->i_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->cluster_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/ ->writepages.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/0bf1a02494c7eb5bd43445de4c83c8592e02c4bf","https://git.kernel.org/stable/c/0df713a9c082a474c8b0bcf670edc8e98461d5a0","https://git.kernel.org/stable/c/10b591e7fb7cdc8c1e53e9c000dc0ef7069aaa76","https://git.kernel.org/stable/c/ad26bfbc085c939b5dca77ff8c14798c06d151c4","https://git.kernel.org/stable/c/bcd0086ee5a2e88c1224ff2ec1e4a43c83efe5a0"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:19:41.481987139+00:00"},"epss":{"cve":"CVE-2025-68772","score":0.00201,"percentile":0.10027,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}