============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz-executor/5609 is trying to acquire lock:
ffff8881be401038 (rhashtable_bucket){-.-.}-{0:0}, at: rht_lock+0x8b/0x180

but task is already holding lock:
ffff8881bd6c4038 (rhashtable_bucket){-.-.}-{0:0}, at: rht_lock+0x8b/0x180

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

       CPU0
       ----
  lock(rhashtable_bucket);
  lock(rhashtable_bucket);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by syz-executor/5609:
 #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: pidfs_add_pid+0x169/0xc50
 #1: ffff8881bd6c4038 (rhashtable_bucket){-.-.}-{0:0}, at: rht_lock+0x8b/0x180
 #2: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: trace_call_bpf+0xb6/0xb80
 #3: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rhtab_map_delete_elem+0x21/0x190
 #4: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rhtab_delete_elem+0x15c/0x1b30

stack backtrace:
CPU: 0 UID: 0 PID: 5609 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_deadlock_bug+0x279/0x290
 __lock_acquire+0x24df/0x2cf0
 lock_acquire+0x106/0x350
 rht_lock+0xa3/0x180
 rhtab_delete_elem+0x404/0x1b30
 rhtab_map_delete_elem+0xe2/0x190
 bpf_prog_a4f1e23443ac9f8e+0x4e/0x56
 trace_call_bpf+0x3f0/0xb80
 perf_trace_run_bpf_submit+0x78/0x170
 perf_trace_lock+0x32d/0x410
 lock_release+0x38e/0x3c0
 pidfs_add_pid+0x650/0xc50
 alloc_pid+0xe7a/0x1310
 copy_process+0x20ea/0x4390
 kernel_clone+0x2d7/0x940
 __x64_sys_clone+0x1b6/0x230
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feecdfc6912
Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffd30d63bd0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffd30d63bd0 RCX: 00007feecdfc6912
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffd30d63d5c R08: 0000000000000000 R09: 0000000000000001
R10: 000055558ad547d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 000000000008dc6a R15: 00007ffd30d63db0
 </TASK>
