{"cve":"CVE-2025-22111","nvd":{"published":"2025-04-16T15:16:05.347","modified":"2026-10-15T02:17:45.380","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: Remove RTNL dance for SIOCBRADDIF and SIOCBRDELIF.\n\nSIOCBRDELIF is passed to dev_ioctl() first and later forwarded to\nbr_ioctl_call(), which causes unnecessary RTNL dance and the splat\nbelow [0] under RTNL pressure.\n\nLet's say Thread A is trying to detach a device from a bridge and\nThread B is trying to remove the bridge.\n\nIn dev_ioctl(), Thread A bumps the bridge device's refcnt by\nnetdev_hold() and releases RTNL because the following br_ioctl_call()\nalso re-acquires RTNL.\n\nIn the race window, Thread B could acquire RTNL and try to remove\nthe bridge device.  Then, rtnl_unlock() by Thread B will release RTNL\nand wait for netdev_put() by Thread A.\n\nThread A, however, must hold RTNL after the unlock in dev_ifsioc(),\nwhich may take long under RTNL pressure, resulting in the splat by\nThread B.\n\n  Thread A (SIOCBRDELIF)           Thread B (SIOCBRDELBR)\n  ----------------------           ----------------------\n  sock_ioctl                       sock_ioctl\n  `- sock_do_ioctl                 `- br_ioctl_call\n     `- dev_ioctl                     `- br_ioctl_stub\n        |- rtnl_lock                     |\n        |- dev_ifsioc                    '\n        '  |- dev = __dev_get_by_name(...)\n           |- netdev_hold(dev, ...)      .\n       /   |- rtnl_unlock  ------.       |\n       |   |- br_ioctl_call       `--->  |- rtnl_lock\n  Race |   |  `- br_ioctl_stub           |- br_del_bridge\n  Window   |     |                       |  |- dev = __dev_get_by_name(...)\n       |   |     |  May take long        |  `- br_dev_delete(dev, ...)\n       |   |     |  under RTNL pressure  |     `- unregister_netdevice_queue(dev, ...)\n       |   |     |               |       `- rtnl_unlock\n       \\   |     |- rtnl_lock  <-'          `- netdev_run_todo\n           |     |- ...                        `- netdev_run_todo\n           |     `- rtnl_unlock                   |- __rtnl_unlock\n           |                                      |- netdev_wait_allrefs_any\n           |- netdev_put(dev, ...)  <----------------'\n                                                Wait refcnt decrement\n                                                and log splat below\n\nTo avoid blocking SIOCBRDELBR unnecessarily, let's not call\ndev_ioctl() for SIOCBRADDIF and SIOCBRDELIF.\n\nIn the dev_ioctl() path, we do the following:\n\n  1. Copy struct ifreq by get_user_ifreq in sock_do_ioctl()\n  2. Check CAP_NET_ADMIN in dev_ioctl()\n  3. Call dev_load() in dev_ioctl()\n  4. Fetch the master dev from ifr.ifr_name in dev_ifsioc()\n\n3. can be done by request_module() in br_ioctl_call(), so we move\n1., 2., and 4. to br_ioctl_stub().\n\nNote that 2. is also checked later in add_del_if(), but it's better\nperformed before RTNL.\n\nSIOCBRADDIF and SIOCBRDELIF have been processed in dev_ioctl() since\nthe pre-git era, and there seems to be no specific reason to process\nthem there.\n\n[0]:\nunregister_netdevice: waiting for wpan3 to become free. Usage count = 2\nref_tracker: wpan3@ffff8880662d8608 has 1/1 users at\n     __netdev_tracker_alloc include/linux/netdevice.h:4282 [inline]\n     netdev_hold include/linux/netdevice.h:4311 [inline]\n     dev_ifsioc+0xc6a/0x1160 net/core/dev_ioctl.c:624\n     dev_ioctl+0x255/0x10c0 net/core/dev_ioctl.c:826\n     sock_do_ioctl+0x1ca/0x260 net/socket.c:1213\n     sock_ioctl+0x23a/0x6c0 net/socket.c:1318\n     vfs_ioctl fs/ioctl.c:51 [inline]\n     __do_sys_ioctl fs/ioctl.c:906 [inline]\n     __se_sys_ioctl fs/ioctl.c:892 [inline]\n     __x64_sys_ioctl+0x1a4/0x210 fs/ioctl.c:892\n     do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n     do_syscall_64+0xcb/0x250 arch/x86/entry/common.c:83\n     entry_SYSCALL_64_after_hwframe+0x77/0x7f","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/00fe0ac64efd1f5373b3dd9f1f84b19235371e39","https://git.kernel.org/stable/c/338a0f3c66aef4ee13052880d02200aae8f2d8a8","https://git.kernel.org/stable/c/4888e1dcc341e9a132ef7b8516234b3c3296de56","https://git.kernel.org/stable/c/d767ce15045df510f55cdd2af5df0eee71f928d0","https://git.kernel.org/stable/c/ed3ba9b6e280e14cc3148c1b226ba453f02fa76c"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:01:11.054312287+00:00"},"epss":{"cve":"CVE-2025-22111","score":0.00205,"percentile":0.10434,"date":"2026-10-25"},"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."]}