============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- kworker/u4:13/15556 is trying to acquire lock: ffff88802c21c1e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88802c21c1e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: unix_collect_skb+0x15a/0x550 net/unix/garbage.c:363 but task is already holding lock: ffff88802c21d1e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88802c21d1e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: unix_collect_skb+0xb7/0x550 net/unix/garbage.c:355 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(rlock-AF_UNIX); lock(rlock-AF_UNIX); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by kworker/u4:13/15556: #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc90004507d00 (unix_gc_work){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #2: ffffffff8de4b838 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #2: ffffffff8de4b838 (unix_gc_lock){+.+.}-{2:2}, at: __unix_gc+0xc4/0x19b0 net/unix/garbage.c:563 #3: ffff88802c21d1e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #3: ffff88802c21d1e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: unix_collect_skb+0xb7/0x550 net/unix/garbage.c:355 stack backtrace: CPU: 1 PID: 15556 Comm: kworker/u4:13 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: events_unbound __unix_gc Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 __lock_acquire+0x123e/0x7d10 kernel/locking/lockdep.c:-1 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] unix_collect_skb+0x15a/0x550 net/unix/garbage.c:363 __unix_walk_scc net/unix/garbage.c:486 [inline] unix_walk_scc net/unix/garbage.c:517 [inline] __unix_gc+0x1107/0x19b0 net/unix/garbage.c:575 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready bridge0: port 1(bridge_slave_0) entered blocking state bridge0: port 1(bridge_slave_0) entered forwarding state IPv6: ADDRCONF(NETDEV_CHANGE): bridge0: link becomes ready netdevsim netdevsim7 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim7 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim7 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim7 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0 device hsr_slave_0 left promiscuous mode device hsr_slave_1 left promiscuous mode batman_adv: batadv0: Interface deactivated: batadv_slave_0 batman_adv: batadv0: Removing interface: batadv_slave_0 batman_adv: batadv0: Interface deactivated: batadv_slave_1 batman_adv: batadv0: Removing interface: batadv_slave_1 bridge0: port 2(bridge_slave_1) entered disabled state device bridge_slave_0 left promiscuous mode bridge0: port 1(bridge_slave_0) entered disabled state device veth1_macvtap left promiscuous mode device veth0_macvtap left promiscuous mode device veth1_vlan left promiscuous mode device veth0_vlan left promiscuous mode team0 (unregistering): Port device team_slave_1 removed team0 (unregistering): Port device team_slave_0 removed bond0 (unregistering): (slave bond_slave_1): Releasing backup interface bond0 (unregistering): (slave bond_slave_0): Releasing backup interface bond0 (unregistering): Released all slaves