{"id":"CVE-2026-99061","summary":"wifi: brcmfmac: fix P2P device removal race in brcmf_detach()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: brcmfmac: fix P2P device removal race in brcmf_detach()\n\nWhen the driver is removed while the user space process that created\nthe P2P device (e.g. wpa_supplicant) is still exiting, the P2P device\ninterface is removed twice and the kernel crashes.\n\nThe two paths are:\n\n - wpa_supplicant, on exit, sends NL80211_CMD_DEL_INTERFACE for the P2P\n   device. nl80211_del_interface() holds RTNL and the wiphy mutex and\n   calls brcmf_p2p_del_vif(), which disables discovery and waits up to\n   1.5 s for BRCMF_E_IF_DEL. Then it calls brcmf_remove_interface(),\n   which unregisters the wdev and frees the vif and the ifp.\n\n - brcmf_detach() sets the bus down, so BRCMF_E_IF_DEL never arrives,\n   and calls brcmf_remove_interface(ifp, false) for the same ifp.\n   brcmf_p2p_ifp_removed() reads ifp-\u003evif and then blocks on\n   rtnl_lock(). When brcmf_p2p_del_vif() releases RTNL, it calls\n   cfg80211_unregister_wdev() on the wdev that was already unregistered\n   and freed.\n\nThe second list_del_rcu() of wdev-\u003elist faults on LIST_POISON2:\n\n  brcmfmac: brcmf_p2p_del_vif delete P2P vif\n  brcmfmac: brcmf_p2p_deinit_discovery enter\n  brcmfmac: brcmf_p2p_del_vif P2P: GO_NEG_PHASE status cleared\n  brcmfmac: brcmf_detach Enter\n  brcmfmac: brcmf_bus_change_state 1 -\u003e 0\n  brcmfmac: brcmf_remove_interface Enter, bsscfgidx=1, ifidx=0\n  brcmfmac: brcmf_del_if Enter, bsscfgidx=1, ifidx=0\n  brcmfmac: brcmf_p2p_ifp_removed P2P: device interface removed\n  [1.5 s later, brcmf_p2p_del_vif() timed out]\n  brcmfmac: brcmf_remove_interface Enter, bsscfgidx=1, ifidx=0\n  brcmfmac: brcmf_del_if Enter, bsscfgidx=1, ifidx=0\n  brcmfmac: brcmf_p2p_ifp_removed P2P: device interface removed\n  Unable to handle kernel paging request at virtual address dead000000000122\n  Internal error: Oops: 96000044 [#1] PREEMPT_RT SMP\n  pc : _cfg80211_unregister_wdev+0x6c/0x264 [cfg80211]\n  Call trace:\n   _cfg80211_unregister_wdev+0x6c/0x264 [cfg80211]\n   cfg80211_unregister_wdev+0x10/0x1c [cfg80211]\n   brcmf_p2p_ifp_removed+0x84/0xb0 [brcmfmac]\n   brcmf_remove_interface+0x1f4/0x254 [brcmfmac]\n   brcmf_detach+0x88/0x180 [brcmfmac]\n   brcmf_sdio_remove+0x90/0x7b0 [brcmfmac]\n   brcmf_sdiod_remove+0x20/0xa0 [brcmfmac]\n   brcmf_ops_sdio_remove+0xbc/0x12c [brcmfmac]\n   sdio_bus_remove+0x38/0x144\n   device_release_driver_internal+0x1e8/0x2c0\n   device_release_driver+0x14/0x20\n   brcmf_sdio_bus_remove+0x2c/0x40 [brcmfmac]\n   brcmf_fwvid_unregister_vendor+0xd8/0x170 [brcmfmac]\n   __exit_compat+0x18/0x418 [brcmfmac_cyw]\n   __arm64_sys_delete_module+0x1ac/0x244\n\nThe log was taken with debug=0x406 on an i.MX 8M Plus board with a\nCYW55513 (Sona IF513) on SDIO. The driver is the Ezurio backport of\nbrcmfmac from v6.18.22 on a 5.4-rt kernel. The code involved is the same\nin mainline.\n\nTo reproduce:\n\n  1. Start wpa_supplicant on wlan0 and let it associate. It creates the\n     P2P device (iw dev shows \"type P2P-device\").\n  2. Stop wpa_supplicant and remove the driver without waiting for\n     wpa_supplicant to exit:\n\n       kill $(pidof wpa_supplicant)\n       rmmod brcmfmac_cyw brcmfmac\n\nThe crash is reproducible on that board.\n\nFor the interface without a netdev (the P2P device), take RTNL and the\nwiphy mutex in brcmf_detach() before reading iflist, and remove it with\nlocked=true. If brcmf_p2p_del_vif() runs first, brcmf_detach() finds the\nslot empty. If brcmf_detach() runs first, nl80211 does not find the wdev\nany more. The interfaces with a netdev are removed as before, because\nbrcmf_del_if() takes RTNL on its own for the primary interface.","modified":"2026-11-04T14:27:27.068912396Z","published":"2026-10-23T12:22:59.770Z","related":["SUSE-SU-2026:5091-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99061.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/08a3f02fea636e97a7422d1512f76dacdb5b0887"},{"type":"WEB","url":"https://git.kernel.org/stable/c/0f84eec09039deb9229fd35c55912a2397d3ae55"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2e0c8c60a11b3177e7432c71d41249e276a0825f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/47ca6395a1d91545cc9403f9218bc61be941a0c3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/75e917473e20dea61f837f9afb5fc3435c9200d2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7b79131e357c4786765b20a994ad40d4d35f2163"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c4c0659eb74f807e0e73742b101a07b0bb703d97"},{"type":"WEB","url":"https://git.kernel.org/stable/c/eef16a74ff8ed2a838d6bb862bb2c7783fce7466"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99061.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99061"},{"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":"9831bcb987df4aff6a1d85975f1dda4c654f298d"},{"fixed":"75e917473e20dea61f837f9afb5fc3435c9200d2"},{"fixed":"c4c0659eb74f807e0e73742b101a07b0bb703d97"},{"fixed":"0f84eec09039deb9229fd35c55912a2397d3ae55"},{"fixed":"7b79131e357c4786765b20a994ad40d4d35f2163"},{"fixed":"2e0c8c60a11b3177e7432c71d41249e276a0825f"},{"fixed":"eef16a74ff8ed2a838d6bb862bb2c7783fce7466"},{"fixed":"47ca6395a1d91545cc9403f9218bc61be941a0c3"},{"fixed":"08a3f02fea636e97a7422d1512f76dacdb5b0887"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-99061.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.4.0"},{"fixed":"5.10.273"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.224"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.191"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.160"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.113"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.57"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-99061.json"}}],"schema_version":"1.9.2"}