====================================================== WARNING: possible circular locking dependency detected 6.9.0-rc4-syzkaller-00031-g96fca68c4fbf #0 Not tainted ------------------------------------------------------ kworker/u32:0/10 is trying to acquire lock: ffff888025cbba00 (&stab->lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff888025cbba00 (&stab->lock){+.-.}-{2:2}, at: __sock_map_delete+0x43/0xe0 net/core/sock_map.c:417 but task is already holding lock: ffff8880414c5290 (&psock->link_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff8880414c5290 (&psock->link_lock){+...}-{2:2}, at: sock_map_del_link net/core/sock_map.c:145 [inline] ffff8880414c5290 (&psock->link_lock){+...}-{2:2}, at: sock_map_unref+0xbf/0x6e0 net/core/sock_map.c:180 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&psock->link_lock){+...}-{2:2}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] sock_map_add_link net/core/sock_map.c:134 [inline] sock_map_update_common+0x622/0x870 net/core/sock_map.c:503 sock_map_update_elem_sys+0x3bb/0x570 net/core/sock_map.c:582 bpf_map_update_value+0x36c/0x6c0 kernel/bpf/syscall.c:172 map_update_elem+0x623/0x910 kernel/bpf/syscall.c:1641 __sys_bpf+0xab9/0x4b40 kernel/bpf/syscall.c:5648 __do_sys_bpf kernel/bpf/syscall.c:5767 [inline] __se_sys_bpf kernel/bpf/syscall.c:5765 [inline] __x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:5765 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&stab->lock){+.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] __sock_map_delete+0x43/0xe0 net/core/sock_map.c:417 sock_map_delete_elem+0xb5/0x100 net/core/sock_map.c:449 ___bpf_prog_run+0x3e51/0xabd0 kernel/bpf/core.c:1997 __bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline] __bpf_prog_run include/linux/filter.h:657 [inline] bpf_prog_run include/linux/filter.h:664 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline] bpf_trace_run2+0x151/0x420 kernel/trace/bpf_trace.c:2420 trace_kfree include/trace/events/kmem.h:94 [inline] kfree+0x225/0x390 mm/slub.c:4377 sk_psock_free_link include/linux/skmsg.h:421 [inline] sock_map_del_link net/core/sock_map.c:158 [inline] sock_map_unref+0x392/0x6e0 net/core/sock_map.c:180 sock_map_free+0x260/0x470 net/core/sock_map.c:351 bpf_map_free_deferred+0x1ce/0x420 kernel/bpf/syscall.c:734 process_one_work+0x9a9/0x1ac0 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 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(&psock->link_lock); lock(&stab->lock); lock(&psock->link_lock); lock(&stab->lock); *** DEADLOCK *** 6 locks held by kworker/u32:0/10: #0: ffff888015091148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1296/0x1ac0 kernel/workqueue.c:3229 #1: ffffc900000d7d80 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work+0x906/0x1ac0 kernel/workqueue.c:3230 #2: ffff8880507e3258 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1671 [inline] #2: ffff8880507e3258 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: sock_map_free+0x20f/0x470 net/core/sock_map.c:349 #3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: sock_map_free+0x231/0x470 net/core/sock_map.c:350 #4: ffff8880414c5290 (&psock->link_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #4: ffff8880414c5290 (&psock->link_lock){+...}-{2:2}, at: sock_map_del_link net/core/sock_map.c:145 [inline] #4: ffff8880414c5290 (&psock->link_lock){+...}-{2:2}, at: sock_map_unref+0xbf/0x6e0 net/core/sock_map.c:180 #5: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #5: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #5: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2380 [inline] #5: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xe4/0x420 kernel/trace/bpf_trace.c:2420 stack backtrace: CPU: 0 PID: 10 Comm: kworker/u32:0 Not tainted 6.9.0-rc4-syzkaller-00031-g96fca68c4fbf #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Workqueue: events_unbound bpf_map_free_deferred Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] __sock_map_delete+0x43/0xe0 net/core/sock_map.c:417 sock_map_delete_elem+0xb5/0x100 net/core/sock_map.c:449 ___bpf_prog_run+0x3e51/0xabd0 kernel/bpf/core.c:1997 __bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline] __bpf_prog_run include/linux/filter.h:657 [inline] bpf_prog_run include/linux/filter.h:664 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline] bpf_trace_run2+0x151/0x420 kernel/trace/bpf_trace.c:2420 trace_kfree include/trace/events/kmem.h:94 [inline] kfree+0x225/0x390 mm/slub.c:4377 sk_psock_free_link include/linux/skmsg.h:421 [inline] sock_map_del_link net/core/sock_map.c:158 [inline] sock_map_unref+0x392/0x6e0 net/core/sock_map.c:180 sock_map_free+0x260/0x470 net/core/sock_map.c:351 bpf_map_free_deferred+0x1ce/0x420 kernel/bpf/syscall.c:734 process_one_work+0x9a9/0x1ac0 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244