From: Cen Zhang Date: Fri, 19 Jun 2026 16:25:42 +0000 (+0800) Subject: wifi: cfg80211: cancel sched scan results work on unregister X-Git-Tag: v7.2-rc4~17^2~16^2~41 X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=edf0730be33696a1bd142792830d392129e495cc;p=thirdparty%2Fkernel%2Flinux.git wifi: cfg80211: cancel sched scan results work on unregister cfg80211_sched_scan_results() can queue rdev->sched_scan_res_wk from a driver result notification while a scheduled scan request is present. The work callback recovers the containing cfg80211_registered_device and then locks the wiphy and walks the scheduled-scan request list. wiphy_unregister() already makes the wiphy unreachable and drains rdev work items before cfg80211_dev_free() can release the object, but it does not drain sched_scan_res_wk. A queued or running result work item can therefore cross the unregister/free boundary and access freed rdev state. The buggy scenario involves two paths, with each column showing the order within that path: scheduled-scan result path: unregister/free path: 1. cfg80211_sched_scan_results() 1. interface teardown stops and queues rdev->sched_scan_res_wk. removes the scheduled scan request. 2. cfg80211_wq starts the work 2. wiphy_unregister() drains other item and recovers rdev. rdev work items. 3. The worker locks rdev->wiphy 3. cfg80211_dev_free() destroys and and walks rdev state. frees rdev. Cancel sched_scan_res_wk in wiphy_unregister() alongside the other rdev work items. cancel_work_sync() removes a pending result notification and waits for an already running callback, so cfg80211_dev_free() cannot free rdev while this work item is still active. Validation reproduced this kernel report: BUG: KASAN: use-after-free in cfg80211_sched_scan_results_wk+0x4a6/0x530 Workqueue: cfg80211 cfg80211_sched_scan_results_wk [cfg80211] Read of size 8 Call trace: dump_stack_lvl+0x66/0xa0 print_report+0xce/0x630 cfg80211_sched_scan_results_wk+0x4a6/0x530 srso_alias_return_thunk+0x5/0xfbef5 __virt_addr_valid+0x224/0x430 kasan_report+0xac/0xe0 lockdep_hardirqs_on_prepare+0xea/0x1a0 process_one_work+0x8d0/0x18f0 (kernel/workqueue.c:3212) lock_is_held_type+0x8f/0x100 worker_thread+0x5ad/0xfd0 __kthread_parkme+0xc6/0x200 kthread+0x31e/0x410 trace_hardirqs_on+0x1a/0x170 ret_from_fork+0x576/0x810 __switch_to+0x57e/0xe20 __switch_to_asm+0x33/0x70 ret_from_fork_asm+0x1a/0x30 Fixes: 807f8a8c3004 ("cfg80211/nl80211: add support for scheduled scans") Assisted-by: Codex:gpt-5.5 Signed-off-by: Cen Zhang Link: https://patch.msgid.link/20260619162542.3878296-1-zzzccc427@gmail.com Signed-off-by: Johannes Berg --- diff --git a/net/wireless/core.c b/net/wireless/core.c index 3dcf63b04c41..2c729a7aca12 100644 --- a/net/wireless/core.c +++ b/net/wireless/core.c @@ -1335,6 +1335,7 @@ void wiphy_unregister(struct wiphy *wiphy) /* this has nothing to do now but make sure it's gone */ cancel_work_sync(&rdev->wiphy_work); + cancel_work_sync(&rdev->sched_scan_res_wk); cancel_work_sync(&rdev->rfkill_block); cancel_work_sync(&rdev->conn_work); flush_work(&rdev->event_work);