syzbot


net-next test error: possible deadlock in ieee80211_remove_interfaces

Status: internal: reported on 2025/01/16 11:22
Subsystems: wireless
[Documentation on labels]
Fix commit: e759e1e4a4bd net: revert RTNL changes in unregister_netdevice_many_notify()
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu-native-arm64-kvm ci-qemu2-arm32 ci-upstream-bpf-kasan-gce]
First crash: 24d, last: 18d

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc7-syzkaller-01620-gcf33d96f5090 #0 Not tainted
------------------------------------------------------
kworker/u8:8/4898 is trying to acquire lock:
ffffffff8fcb4e08 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_acquire_if_cleanup_net net/core/dev.c:10272 [inline]
ffffffff8fcb4e08 (rtnl_mutex){+.+.}-{4:4}, at: unregister_netdevice_many_notify+0xac2/0x2030 net/core/dev.c:11792

but task is already holding lock:
ffff888067db8768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6061 [inline]
ffff888067db8768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: ieee80211_remove_interfaces+0x129/0x700 net/mac80211/iface.c:2280

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&rdev->wiphy.mtx){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
       wiphy_lock include/net/cfg80211.h:6046 [inline]
       wiphy_register+0x1a49/0x27b0 net/wireless/core.c:1006
       ieee80211_register_hw+0x354e/0x4240 net/mac80211/main.c:1587
       mac80211_hwsim_new_radio+0x2a9f/0x4a90 drivers/net/wireless/virtual/mac80211_hwsim.c:5558
       init_mac80211_hwsim+0x87a/0xb00 drivers/net/wireless/virtual/mac80211_hwsim.c:6910
       do_one_initcall+0x248/0x870 init/main.c:1266
       do_initcall_level+0x157/0x210 init/main.c:1328
       do_initcalls+0x3f/0x80 init/main.c:1344
       kernel_init_freeable+0x435/0x5d0 init/main.c:1577
       kernel_init+0x1d/0x2b0 init/main.c:1466
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (rtnl_mutex){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3161 [inline]
       check_prevs_add kernel/locking/lockdep.c:3280 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
       __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
       rtnl_acquire_if_cleanup_net net/core/dev.c:10272 [inline]
       unregister_netdevice_many_notify+0xac2/0x2030 net/core/dev.c:11792
       unregister_netdevice_many net/core/dev.c:11875 [inline]
       unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11741
       unregister_netdevice include/linux/netdevice.h:3329 [inline]
       _cfg80211_unregister_wdev+0x163/0x590 net/wireless/core.c:1251
       ieee80211_remove_interfaces+0x4ef/0x700 net/mac80211/iface.c:2305
       ieee80211_unregister_hw+0x5d/0x2c0 net/mac80211/main.c:1681
       mac80211_hwsim_del_radio+0x2c4/0x4c0 drivers/net/wireless/virtual/mac80211_hwsim.c:5664
       hwsim_exit_net+0x5c1/0x670 drivers/net/wireless/virtual/mac80211_hwsim.c:6544
       ops_exit_list net/core/net_namespace.c:172 [inline]
       cleanup_net+0x812/0xd60 net/core/net_namespace.c:652
       process_one_work kernel/workqueue.c:3236 [inline]
       process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
       worker_thread+0x870/0xd30 kernel/workqueue.c:3398
       kthread+0x2f0/0x390 kernel/kthread.c:389
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&rdev->wiphy.mtx);
                               lock(rtnl_mutex);
                               lock(&rdev->wiphy.mtx);
  lock(rtnl_mutex);

 *** DEADLOCK ***

4 locks held by kworker/u8:8/4898:
 #0: ffff88801baf5948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
 #0: ffff88801baf5948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3317
 #1: ffffc900105c7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
 #1: ffffc900105c7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3317
 #2: ffffffff8fca8850 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0x17a/0xd60 net/core/net_namespace.c:606
 #3: ffff888067db8768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6061 [inline]
 #3: ffff888067db8768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: ieee80211_remove_interfaces+0x129/0x700 net/mac80211/iface.c:2280

stack backtrace:
CPU: 0 UID: 0 PID: 4898 Comm: kworker/u8:8 Not tainted 6.13.0-rc7-syzkaller-01620-gcf33d96f5090 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206
 check_prev_add kernel/locking/lockdep.c:3161 [inline]
 check_prevs_add kernel/locking/lockdep.c:3280 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
 __mutex_lock_common kernel/locking/mutex.c:585 [inline]
 __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
 rtnl_acquire_if_cleanup_net net/core/dev.c:10272 [inline]
 unregister_netdevice_many_notify+0xac2/0x2030 net/core/dev.c:11792
 unregister_netdevice_many net/core/dev.c:11875 [inline]
 unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11741
 unregister_netdevice include/linux/netdevice.h:3329 [inline]
 _cfg80211_unregister_wdev+0x163/0x590 net/wireless/core.c:1251
 ieee80211_remove_interfaces+0x4ef/0x700 net/mac80211/iface.c:2305
 ieee80211_unregister_hw+0x5d/0x2c0 net/mac80211/main.c:1681
 mac80211_hwsim_del_radio+0x2c4/0x4c0 drivers/net/wireless/virtual/mac80211_hwsim.c:5664
 hwsim_exit_net+0x5c1/0x670 drivers/net/wireless/virtual/mac80211_hwsim.c:6544
 ops_exit_list net/core/net_namespace.c:172 [inline]
 cleanup_net+0x812/0xd60 net/core/net_namespace.c:652
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
 worker_thread+0x870/0xd30 kernel/workqueue.c:3398
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
bridge_slave_1: left allmulticast mode
bridge_slave_1: left promiscuous mode
bridge0: port 2(bridge_slave_1) entered disabled state
bridge_slave_0: left allmulticast mode
bridge_slave_0: left promiscuous mode
bridge0: port 1(bridge_slave_0) entered disabled state
bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
bond0 (unregistering): Released all slaves
hsr_slave_0: left promiscuous mode
hsr_slave_1: left promiscuous mode
batman_adv: batadv0: Removing interface: batadv_slave_0
batman_adv: batadv0: Removing interface: batadv_slave_1
team0 (unregistering): Port device team_slave_1 removed
team0 (unregistering): Port device team_slave_0 removed

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/22 14:54 net-next cf33d96f5090 25e17fd3 .config console log report [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce net-next test error: possible deadlock in ieee80211_remove_interfaces
2025/01/22 02:10 net-next cf33d96f5090 da72ac06 .config console log report [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce net-next test error: possible deadlock in ieee80211_remove_interfaces
2025/01/21 19:12 net-next cf33d96f5090 6e87cfa2 .config console log report [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce net-next test error: possible deadlock in ieee80211_remove_interfaces
2025/01/19 05:04 net-next 59372af69d4d f2cb035c .config console log report [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce net-next test error: possible deadlock in ieee80211_remove_interfaces
2025/01/17 15:26 net-next 7d2eba0f83a5 953d1c45 .config console log report [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce net-next test error: possible deadlock in ieee80211_remove_interfaces
2025/01/16 23:48 net-next 2ee738e90e80 f9e07a6e .config console log report [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce net-next test error: possible deadlock in ieee80211_remove_interfaces
2025/01/16 20:41 net-next 2ee738e90e80 968edaf4 .config console log report [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce net-next test error: possible deadlock in ieee80211_remove_interfaces
2025/01/16 12:22 net-next b44e27b4df1a 968edaf4 .config console log report [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce net-next test error: possible deadlock in ieee80211_remove_interfaces
2025/01/16 11:21 net-next 0b21051a4a62 968edaf4 .config console log report [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce net-next test error: possible deadlock in ieee80211_remove_interfaces
* Struck through repros no longer work on HEAD.