{"id":"CVE-2022-49708","summary":"ext4: fix bug_on ext4_mb_use_inode_pa","details":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix bug_on ext4_mb_use_inode_pa\n\nHulk Robot reported a BUG_ON:\n==================================================================\nkernel BUG at fs/ext4/mballoc.c:3211!\n[...]\nRIP: 0010:ext4_mb_mark_diskspace_used.cold+0x85/0x136f\n[...]\nCall Trace:\n ext4_mb_new_blocks+0x9df/0x5d30\n ext4_ext_map_blocks+0x1803/0x4d80\n ext4_map_blocks+0x3a4/0x1a10\n ext4_writepages+0x126d/0x2c30\n do_writepages+0x7f/0x1b0\n __filemap_fdatawrite_range+0x285/0x3b0\n file_write_and_wait_range+0xb1/0x140\n ext4_sync_file+0x1aa/0xca0\n vfs_fsync_range+0xfb/0x260\n do_fsync+0x48/0xa0\n[...]\n==================================================================\n\nAbove issue may happen as follows:\n-------------------------------------\ndo_fsync\n vfs_fsync_range\n  ext4_sync_file\n   file_write_and_wait_range\n    __filemap_fdatawrite_range\n     do_writepages\n      ext4_writepages\n       mpage_map_and_submit_extent\n        mpage_map_one_extent\n         ext4_map_blocks\n          ext4_mb_new_blocks\n           ext4_mb_normalize_request\n            \u003e\u003e\u003e start + size \u003c= ac-\u003eac_o_ex.fe_logical\n           ext4_mb_regular_allocator\n            ext4_mb_simple_scan_group\n             ext4_mb_use_best_found\n              ext4_mb_new_preallocation\n               ext4_mb_new_inode_pa\n                ext4_mb_use_inode_pa\n                 \u003e\u003e\u003e set ac-\u003eac_b_ex.fe_len \u003c= 0\n           ext4_mb_mark_diskspace_used\n            \u003e\u003e\u003e BUG_ON(ac-\u003eac_b_ex.fe_len \u003c= 0);\n\nwe can easily reproduce this problem with the following commands:\n\t`fallocate -l100M disk`\n\t`mkfs.ext4 -b 1024 -g 256 disk`\n\t`mount disk /mnt`\n\t`fsstress -d /mnt -l 0 -n 1000 -p 1`\n\nThe size must be smaller than or equal to EXT4_BLOCKS_PER_GROUP.\nTherefore, \"start + size \u003c= ac-\u003eac_o_ex.fe_logical\" may occur\nwhen the size is truncated. So start should be the start position of\nthe group where ac_o_ex.fe_logical is located after alignment.\nIn addition, when the value of fe_logical or EXT4_BLOCKS_PER_GROUP\nis very large, the value calculated by start_off is more accurate.","modified":"2026-04-02T08:27:51.016463Z","published":"2025-02-26T02:24:26.142Z","related":["SUSE-SU-2025:1027-1","SUSE-SU-2025:1176-1","SUSE-SU-2025:1183-1","SUSE-SU-2025:1194-1","SUSE-SU-2025:1241-1","SUSE-SU-2025:1263-1","SUSE-SU-2025:1293-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49708.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/5707d721d1819db57dba57b1d4623034fcb32047"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6880fb2e64331b9fdc85d3f32b1d7e81ad8703f1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6fdaf31ad5f3d3afab744dfd9a8b0d9142aa881f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/887a3e9ad4b8309a2266bce7ae749b2bf1f7a687"},{"type":"WEB","url":"https://git.kernel.org/stable/c/90f0f9d45dff0128c0fca0d2358c4153b024afa6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a08f789d2ab5242c07e716baf9a835725046be89"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a37c1359714da42517dd19d36fc3c4d17edba832"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a6b31616e5afe1d3972cb0682a373e50597faf5c"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49708.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-49708"},{"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":"fc6c2da174edd7a7b760b12c60d432d300e05cca"},{"fixed":"6880fb2e64331b9fdc85d3f32b1d7e81ad8703f1"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"cd648b8a8fd5071d232242d5ee7ee3c0815776af"},{"fixed":"a37c1359714da42517dd19d36fc3c4d17edba832"},{"fixed":"5707d721d1819db57dba57b1d4623034fcb32047"},{"fixed":"a6b31616e5afe1d3972cb0682a373e50597faf5c"},{"fixed":"6fdaf31ad5f3d3afab744dfd9a8b0d9142aa881f"},{"fixed":"90f0f9d45dff0128c0fca0d2358c4153b024afa6"},{"fixed":"887a3e9ad4b8309a2266bce7ae749b2bf1f7a687"},{"fixed":"a08f789d2ab5242c07e716baf9a835725046be89"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0"},{"last_affected":"f213db429b883a2d5403de0b1ce92fb7d7ee979e"},{"last_affected":"98f58e05231f835dfb09359e3b5e3a886fe8f189"},{"last_affected":"c1664e9bcf6291c0ceb8599f57c8cf493526abe6"},{"last_affected":"37cf4ab1ba60c30ca9fd0fe3b9993b24cb87886a"},{"last_affected":"75f37dab088eb84ff25a49e59371f01ea3f44aa7"},{"last_affected":"8774c73cf6963310395823ed7077ea12943ea0f3"},{"last_affected":"c4fbdc0124799f1772f4d886b7f2e1a6f881d195"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-49708.json"}}],"schema_version":"1.7.5"}