{"id":"CVE-2026-23199","summary":"procfs: avoid fetching build ID while holding VMA lock","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nprocfs: avoid fetching build ID while holding VMA lock\n\nFix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock\nor per-VMA lock, whichever was used to lock VMA under question, to avoid\ndeadlock reported by syzbot:\n\n -\u003e #1 (&mm-\u003emmap_lock){++++}-{4:4}:\n        __might_fault+0xed/0x170\n        _copy_to_iter+0x118/0x1720\n        copy_page_to_iter+0x12d/0x1e0\n        filemap_read+0x720/0x10a0\n        blkdev_read_iter+0x2b5/0x4e0\n        vfs_read+0x7f4/0xae0\n        ksys_read+0x12a/0x250\n        do_syscall_64+0xcb/0xf80\n        entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n -\u003e #0 (&sb-\u003es_type-\u003ei_mutex_key#8){++++}-{4:4}:\n        __lock_acquire+0x1509/0x26d0\n        lock_acquire+0x185/0x340\n        down_read+0x98/0x490\n        blkdev_read_iter+0x2a7/0x4e0\n        __kernel_read+0x39a/0xa90\n        freader_fetch+0x1d5/0xa80\n        __build_id_parse.isra.0+0xea/0x6a0\n        do_procmap_query+0xd75/0x1050\n        procfs_procmap_ioctl+0x7a/0xb0\n        __x64_sys_ioctl+0x18e/0x210\n        do_syscall_64+0xcb/0xf80\n        entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n other info that might help us debug this:\n\n  Possible unsafe locking scenario:\n\n        CPU0                    CPU1\n        ----                    ----\n   rlock(&mm-\u003emmap_lock);\n                                lock(&sb-\u003es_type-\u003ei_mutex_key#8);\n                                lock(&mm-\u003emmap_lock);\n   rlock(&sb-\u003es_type-\u003ei_mutex_key#8);\n\n  *** DEADLOCK ***\n\nThis seems to be exacerbated (as we haven't seen these syzbot reports\nbefore that) by the recent:\n\n\t777a8560fd29 (\"lib/buildid: use __kernel_read() for sleepable context\")\n\nTo make this safe, we need to grab file refcount while VMA is still locked, but\nother than that everything is pretty straightforward. Internal build_id_parse()\nAPI assumes VMA is passed, but it only needs the underlying file reference, so\njust add another variant build_id_parse_file() that expects file passed\ndirectly.\n\n[akpm@linux-foundation.org: fix up kerneldoc]","modified":"2026-03-20T12:47:27.118774Z","published":"2026-02-14T16:27:24.326Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23199.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/b5cbacd7f86f4f62b8813688c8e73be94e8e1951"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b9b97e6aeb534315f9646b2090d1a5024c6a4e82"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cbc03ce3e6ce7e21214c3f02218213574c1a2d08"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23199.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23199"},{"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":"ed5d583a88a9207b866c14ba834984c6f3c51d23"},{"fixed":"b9b97e6aeb534315f9646b2090d1a5024c6a4e82"},{"fixed":"cbc03ce3e6ce7e21214c3f02218213574c1a2d08"},{"fixed":"b5cbacd7f86f4f62b8813688c8e73be94e8e1951"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-23199.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.11.0"},{"fixed":"6.12.70"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-23199.json"}}],"schema_version":"1.7.5"}