======================================================
WARNING: possible circular locking dependency detected
6.9.0-syzkaller-12162-gf85af9d955ac #0 Not tainted
------------------------------------------------------
kworker/u8:6/141 is trying to acquire lock:
ffff88802b89c220 (&stab->lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff88802b89c220 (&stab->lock){+.-.}-{2:2}, at: __sock_map_delete net/core/sock_map.c:429 [inline]
ffff88802b89c220 (&stab->lock){+.-.}-{2:2}, at: sock_map_delete_elem+0x175/0x250 net/core/sock_map.c:461

but task is already holding lock:
ffff88805f1a82b0 (&psock->link_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff88805f1a82b0 (&psock->link_lock){+...}-{2:2}, at: sock_map_del_link net/core/sock_map.c:157 [inline]
ffff88805f1a82b0 (&psock->link_lock){+...}-{2:2}, at: sock_map_unref+0xcc/0x5e0 net/core/sock_map.c:192

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&psock->link_lock){+...}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
       _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:356 [inline]
       sock_map_add_link net/core/sock_map.c:146 [inline]
       sock_map_update_common+0x31c/0x5b0 net/core/sock_map.c:515
       sock_map_update_elem_sys+0x55f/0x910 net/core/sock_map.c:594
       map_update_elem+0x53a/0x6f0 kernel/bpf/syscall.c:1654
       __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5697
       __do_sys_bpf kernel/bpf/syscall.c:5816 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:5814 [inline]
       __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5814
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 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+0x18e0/0x5900 kernel/locking/lockdep.c:3869
       __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
       _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
       spin_lock_bh include/linux/spinlock.h:356 [inline]
       __sock_map_delete net/core/sock_map.c:429 [inline]
       sock_map_delete_elem+0x175/0x250 net/core/sock_map.c:461
       bpf_prog_78b015942f8c5b4e+0x63/0x67
       bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline]
       __bpf_prog_run include/linux/filter.h:691 [inline]
       bpf_prog_run include/linux/filter.h:698 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2403 [inline]
       bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2444
       trace_kfree include/trace/events/kmem.h:94 [inline]
       kfree+0x2bb/0x360 mm/slub.c:4544
       sk_psock_free_link include/linux/skmsg.h:423 [inline]
       sock_map_del_link net/core/sock_map.c:170 [inline]
       sock_map_unref+0x3ac/0x5e0 net/core/sock_map.c:192
       sock_map_free+0x1e9/0x3d0 net/core/sock_map.c:363
       bpf_map_free_deferred+0xe6/0x110 kernel/bpf/syscall.c:746
       process_one_work kernel/workqueue.c:3231 [inline]
       process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
       worker_thread+0x86d/0xd70 kernel/workqueue.c:3393
       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(&psock->link_lock);
                               lock(&stab->lock);
                               lock(&psock->link_lock);
  lock(&stab->lock);

 *** DEADLOCK ***

6 locks held by kworker/u8:6/141:
 #0: ffff888015089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline]
 #0: ffff888015089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312
 #1: ffffc90002d77d00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline]
 #1: ffffc90002d77d00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312
 #2: ffff88806acaa258 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1602 [inline]
 #2: ffff88806acaa258 (sk_lock-AF_UNIX){+.+.}-{0:0}, at: sock_map_free+0x128/0x3d0 net/core/sock_map.c:361
 #3: ffffffff8e333e60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #3: ffffffff8e333e60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #3: ffffffff8e333e60 (rcu_read_lock){....}-{1:2}, at: sock_map_free+0x134/0x3d0 net/core/sock_map.c:362
 #4: ffff88805f1a82b0 (&psock->link_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
 #4: ffff88805f1a82b0 (&psock->link_lock){+...}-{2:2}, at: sock_map_del_link net/core/sock_map.c:157 [inline]
 #4: ffff88805f1a82b0 (&psock->link_lock){+...}-{2:2}, at: sock_map_unref+0xcc/0x5e0 net/core/sock_map.c:192
 #5: ffffffff8e333e60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #5: ffffffff8e333e60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #5: ffffffff8e333e60 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2402 [inline]
 #5: ffffffff8e333e60 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x1fc/0x540 kernel/trace/bpf_trace.c:2444

stack backtrace:
CPU: 1 PID: 141 Comm: kworker/u8:6 Not tainted 6.9.0-syzkaller-12162-gf85af9d955ac #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 check_noncircular+0x36a/0x4a0 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+0x18e0/0x5900 kernel/locking/lockdep.c:3869
 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
 _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:356 [inline]
 __sock_map_delete net/core/sock_map.c:429 [inline]
 sock_map_delete_elem+0x175/0x250 net/core/sock_map.c:461
 bpf_prog_78b015942f8c5b4e+0x63/0x67
 bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline]
 __bpf_prog_run include/linux/filter.h:691 [inline]
 bpf_prog_run include/linux/filter.h:698 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2403 [inline]
 bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2444
 trace_kfree include/trace/events/kmem.h:94 [inline]
 kfree+0x2bb/0x360 mm/slub.c:4544
 sk_psock_free_link include/linux/skmsg.h:423 [inline]
 sock_map_del_link net/core/sock_map.c:170 [inline]
 sock_map_unref+0x3ac/0x5e0 net/core/sock_map.c:192
 sock_map_free+0x1e9/0x3d0 net/core/sock_map.c:363
 bpf_map_free_deferred+0xe6/0x110 kernel/bpf/syscall.c:746
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3393
 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>