syzbot

============================================
WARNING: possible recursive locking detected
5.15.159-syzkaller #0 Not tainted
--------------------------------------------
kworker/0:3/3248 is trying to acquire lock:
ffff88801d87e868 (&htab->buckets[i].lock){+...}-{2:2}, at: sock_hash_delete_elem+0x177/0x400 net/core/sock_map.c:943

but task is already holding lock:
ffff88801d87e868 (&htab->buckets[i].lock){+...}-{2:2}, at: sock_hash_delete_elem+0x177/0x400 net/core/sock_map.c:943

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

       CPU0
       ----
  lock(&htab->buckets[i].lock);
  lock(&htab->buckets[i].lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

6 locks held by kworker/0:3/3248:
 #0: ffff888011c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90002db7d20 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8c91fae0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
 #3: ffff88801d87e868 (&htab->buckets[i].lock){+...}-{2:2}, at: sock_hash_delete_elem+0x177/0x400 net/core/sock_map.c:943
 #4: ffff88807c13e290 (&psock->link_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
 #4: ffff88807c13e290 (&psock->link_lock){+...}-{2:2}, at: sock_map_del_link net/core/sock_map.c:147 [inline]
 #4: ffff88807c13e290 (&psock->link_lock){+...}-{2:2}, at: sock_map_unref+0xcc/0x5d0 net/core/sock_map.c:182
 #5: ffffffff8c91fae0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311

stack backtrace:
CPU: 0 PID: 3248 Comm: kworker/0:3 Not tainted 5.15.159-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Workqueue: events bpf_map_free_deferred
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 print_deadlock_bug kernel/locking/lockdep.c:2946 [inline]
 check_deadlock kernel/locking/lockdep.c:2989 [inline]
 validate_chain+0x46d2/0x5930 kernel/locking/lockdep.c:3775
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
 sock_hash_delete_elem+0x177/0x400 net/core/sock_map.c:943
 bpf_prog_2c29ac5cdc6b1842+0x3a/0x168
 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1880 [inline]
 bpf_trace_run2+0x19e/0x340 kernel/trace/bpf_trace.c:1917
 __bpf_trace_kfree+0x6e/0x90 include/trace/events/kmem.h:118
 trace_kfree include/trace/events/kmem.h:118 [inline]
 kfree+0x22f/0x270 mm/slub.c:4549
 sk_psock_free_link include/linux/skmsg.h:421 [inline]
 sock_map_del_link net/core/sock_map.c:160 [inline]
 sock_map_unref+0x3ac/0x5d0 net/core/sock_map.c:182
 sock_hash_delete_elem+0x388/0x400 net/core/sock_map.c:947
 bpf_prog_2c29ac5cdc6b1842+0x3a/0x168
 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1880 [inline]
 bpf_trace_run2+0x19e/0x340 kernel/trace/bpf_trace.c:1917
 __bpf_trace_kfree+0x6e/0x90 include/trace/events/kmem.h:118
 trace_kfree include/trace/events/kmem.h:118 [inline]
 kfree+0x22f/0x270 mm/slub.c:4549
 sock_hash_free+0x713/0x780 net/core/sock_map.c:1185
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
 </TASK>