{"id":"CVE-2026-90190","summary":"null_blk: use DEFINE_MUTEX for the file-scope mutex","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnull_blk: use DEFINE_MUTEX for the file-scope mutex\n\nIn null_init(), mutex_init(&lock) currently happens after\nconfigfs_register_subsystem(), which exposes the nullb subsystem to\nuserspace. A racing mkdir() into /sys/kernel/config/nullb/ can reach\nnull_find_dev_by_name() -\u003e mutex_lock(&lock) before the mutex is\ninitialized, trigger warning:\n\n[  123.137788] DEBUG_LOCKS_WARN_ON(lock-\u003emagic != lock)\n[  123.137796] WARNING: kernel/locking/mutex.c:159 at mutex_lock+0x171/0x1c0, CPU#13: mkdir/1301\n[  123.140090] Modules linked in: null_blk(+) nft_fib_inet nft_fib_ipv4\n......\n[  123.154926] Call Trace:\n[  123.155172]  \u003cTASK\u003e\n[  123.155419]  ? __pfx_mutex_lock+0x10/0x10\n[  123.156181]  ? __pfx__raw_spin_lock+0x10/0x10\n[  123.156571]  nullb_group_make_group+0x20/0x100 [null_blk]\n[  123.157011]  configfs_mkdir+0x47b/0xc70\n[  123.157337]  ? __pfx_configfs_mkdir+0x10/0x10\n[  123.157719]  ? may_create_dentry+0x242/0x2e0\n[  123.158061]  vfs_mkdir+0x2a9/0x6c0\n[  123.158352]  filename_mkdirat+0x3dc/0x500\n[  123.158710]  ? __pfx_filename_mkdirat+0x10/0x10\n[  123.159070]  ? strncpy_from_user+0x3a/0x1d0\n[  123.159413]  __x64_sys_mkdir+0x6b/0x90\n[  123.159760]  do_syscall_64+0xea/0x600\n\nReplace the runtime mutex_init(&lock) with a static DEFINE_MUTEX(lock)\ndeclaration to fix this issue.","modified":"2026-09-19T03:47:25.129039503Z","published":"2026-09-17T16:07:11.654Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90190.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/017dac7670909eaea3eb36e6b3b5a8be9ce0a14d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/0a8c2f7b95981913ac370683e34db4906970c210"},{"type":"WEB","url":"https://git.kernel.org/stable/c/234117949da3b3f9705a21b66094f9f30bbe681d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/349903f7ee72f7ac5b7a98840d701b2082d140a3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c7dea90c9b4ef1dfbd2e4df36de180c76fd7c33c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f9f4ca45c770b7eec83fea6c9b727b26e691b513"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90190.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90190"},{"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":"49c3b9266a718dbd73c42e004288b4bb2ea0ac0b"},{"fixed":"f9f4ca45c770b7eec83fea6c9b727b26e691b513"},{"fixed":"349903f7ee72f7ac5b7a98840d701b2082d140a3"},{"fixed":"0a8c2f7b95981913ac370683e34db4906970c210"},{"fixed":"c7dea90c9b4ef1dfbd2e4df36de180c76fd7c33c"},{"fixed":"234117949da3b3f9705a21b66094f9f30bbe681d"},{"fixed":"017dac7670909eaea3eb36e6b3b5a8be9ce0a14d"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90190.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.19.0"},{"fixed":"6.1.188"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.157"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.110"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.52"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90190.json"}}],"schema_version":"1.9.0"}