syzbot


possible deadlock in ieee80211_change_mac

Status: fixed on 2023/12/21 01:43
Subsystems: wireless
[Documentation on labels]
Reported-by: syzbot+25b3a0b24216651bc2af@syzkaller.appspotmail.com
Fix commit: 74a7c93f45ab wifi: mac80211: fix change_address deadlock during unregister
First crash: 143d, last: 143d
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] wifi: mac80211: fix change_address deadlock during unregister 1 (1) 2023/10/12 10:34
[syzbot] [net?] [wireless?] possible deadlock in ieee80211_change_mac 0 (1) 2023/10/12 04:15

Sample crash report:
bond3: (slave wlan1): Releasing backup interface
============================================
WARNING: possible recursive locking detected
6.6.0-rc4-syzkaller-01096-g48533eca606e #0 Not tainted
--------------------------------------------
kworker/u4:20/1920 is trying to acquire lock:
ffff888029960768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5870 [inline]
ffff888029960768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: ieee80211_change_mac+0x8c/0x13a0 net/mac80211/iface.c:301

but task is already holding lock:
ffff888029960768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5870 [inline]
ffff888029960768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: ieee80211_remove_interfaces+0xfe/0x750 net/mac80211/iface.c:2253

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&rdev->wiphy.mtx);
  lock(&rdev->wiphy.mtx);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by kworker/u4:20/1920:
 #0: ffff888012c73d38 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x787/0x15c0 kernel/workqueue.c:2605
 #1: ffffc9000fa5fd80 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7e9/0x15c0 kernel/workqueue.c:2606
 #2: ffffffff8e5eedd0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9f/0xb20 net/core/net_namespace.c:576
 #3: ffffffff8e6040e8 (rtnl_mutex){+.+.}-{3:3}, at: ieee80211_unregister_hw+0x4d/0x3a0 net/mac80211/main.c:1486
 #4: ffff888029960768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5870 [inline]
 #4: ffff888029960768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: ieee80211_remove_interfaces+0xfe/0x750 net/mac80211/iface.c:2253

stack backtrace:
CPU: 1 PID: 1920 Comm: kworker/u4:20 Not tainted 6.6.0-rc4-syzkaller-01096-g48533eca606e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 check_deadlock kernel/locking/lockdep.c:3062 [inline]
 validate_chain kernel/locking/lockdep.c:3855 [inline]
 __lock_acquire+0x2971/0x5de0 kernel/locking/lockdep.c:5136
 lock_acquire kernel/locking/lockdep.c:5753 [inline]
 lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x181/0x1340 kernel/locking/mutex.c:747
 wiphy_lock include/net/cfg80211.h:5870 [inline]
 ieee80211_change_mac+0x8c/0x13a0 net/mac80211/iface.c:301
 dev_set_mac_address+0x303/0x4a0 net/core/dev.c:8855
 __bond_release_one+0xb1b/0x17e0 drivers/net/bonding/bond_main.c:2504
 bond_slave_netdev_event drivers/net/bonding/bond_main.c:3888 [inline]
 bond_netdev_event+0xbab/0xd30 drivers/net/bonding/bond_main.c:4006
 notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93
 call_netdevice_notifiers_info+0xb9/0x130 net/core/dev.c:1970
 call_netdevice_notifiers_extack net/core/dev.c:2008 [inline]
 call_netdevice_notifiers net/core/dev.c:2022 [inline]
 unregister_netdevice_many_notify+0x85f/0x1a20 net/core/dev.c:10960
 unregister_netdevice_many net/core/dev.c:11016 [inline]
 unregister_netdevice_queue+0x2e5/0x3c0 net/core/dev.c:10896
 unregister_netdevice include/linux/netdevice.h:3116 [inline]
 _cfg80211_unregister_wdev+0x61c/0x7e0 net/wireless/core.c:1204
 ieee80211_remove_interfaces+0x36d/0x750 net/mac80211/iface.c:2278
 ieee80211_unregister_hw+0x55/0x3a0 net/mac80211/main.c:1493
 mac80211_hwsim_del_radio drivers/net/wireless/virtual/mac80211_hwsim.c:5410 [inline]
 hwsim_exit_net+0x3a8/0x7d0 drivers/net/wireless/virtual/mac80211_hwsim.c:6287
 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:170
 cleanup_net+0x505/0xb20 net/core/net_namespace.c:614
 process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
 kthread+0x33c/0x440 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/10/08 04:04 net-next 48533eca606e 5e837c76 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce possible deadlock in ieee80211_change_mac
* Struck through repros no longer work on HEAD.