{"id":"CVE-2022-50344","summary":"ext4: fix null-ptr-deref in ext4_write_info","details":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix null-ptr-deref in ext4_write_info\n\nI caught a null-ptr-deref bug as follows:\n==================================================================\nKASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f]\nCPU: 1 PID: 1589 Comm: umount Not tainted 5.10.0-02219-dirty #339\nRIP: 0010:ext4_write_info+0x53/0x1b0\n[...]\nCall Trace:\n dquot_writeback_dquots+0x341/0x9a0\n ext4_sync_fs+0x19e/0x800\n __sync_filesystem+0x83/0x100\n sync_filesystem+0x89/0xf0\n generic_shutdown_super+0x79/0x3e0\n kill_block_super+0xa1/0x110\n deactivate_locked_super+0xac/0x130\n deactivate_super+0xb6/0xd0\n cleanup_mnt+0x289/0x400\n __cleanup_mnt+0x16/0x20\n task_work_run+0x11c/0x1c0\n exit_to_user_mode_prepare+0x203/0x210\n syscall_exit_to_user_mode+0x5b/0x3a0\n do_syscall_64+0x59/0x70\n entry_SYSCALL_64_after_hwframe+0x44/0xa9\n ==================================================================\n\nAbove issue may happen as follows:\n-------------------------------------\nexit_to_user_mode_prepare\n task_work_run\n  __cleanup_mnt\n   cleanup_mnt\n    deactivate_super\n     deactivate_locked_super\n      kill_block_super\n       generic_shutdown_super\n        shrink_dcache_for_umount\n         dentry = sb-\u003es_root\n         sb-\u003es_root = NULL              \u003c--- Here set NULL\n        sync_filesystem\n         __sync_filesystem\n          sb-\u003es_op-\u003esync_fs \u003e ext4_sync_fs\n           dquot_writeback_dquots\n            sb-\u003edq_op-\u003ewrite_info \u003e ext4_write_info\n             ext4_journal_start(d_inode(sb-\u003es_root), EXT4_HT_QUOTA, 2)\n              d_inode(sb-\u003es_root)\n               s_root-\u003ed_inode          \u003c--- Null pointer dereference\n\nTo solve this problem, we use ext4_journal_start_sb directly\nto avoid s_root being used.","modified":"2026-04-02T08:28:26.702704Z","published":"2025-09-16T16:11:23.345Z","related":["SUSE-SU-2025:03613-1","SUSE-SU-2025:03614-1","SUSE-SU-2025:03615-1","SUSE-SU-2025:03626-1","SUSE-SU-2025:03628-1","SUSE-SU-2025:3716-1","SUSE-SU-2025:3761-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50344.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4a657319cfabd6199fd0b7b65bbebf6ded7a11c1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/533c60a0b97cee5daab376933f486207e6680fb7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/947264e00c46de19a016fd81218118c708fed2f3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bb420e8afc854d2a1caaa23a0c129839acfb7888"},{"type":"WEB","url":"https://git.kernel.org/stable/c/dc451578446afd03c0c21913993c08898a691435"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f34ab95162763cd7352f46df169296eec28b688d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f4b5ff0b794aa94afac7269c494550ca2f66511b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f9c1f248607d5546075d3f731e7607d5571f2b60"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50344.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-50344"},{"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":"a1177825719ccef3f76ef39bbfd5ebb6087d53c7"},{"fixed":"dc451578446afd03c0c21913993c08898a691435"},{"fixed":"f4b5ff0b794aa94afac7269c494550ca2f66511b"},{"fixed":"947264e00c46de19a016fd81218118c708fed2f3"},{"fixed":"3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4"},{"fixed":"f34ab95162763cd7352f46df169296eec28b688d"},{"fixed":"533c60a0b97cee5daab376933f486207e6680fb7"},{"fixed":"4a657319cfabd6199fd0b7b65bbebf6ded7a11c1"},{"fixed":"bb420e8afc854d2a1caaa23a0c129839acfb7888"},{"fixed":"f9c1f248607d5546075d3f731e7607d5571f2b60"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-50344.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}