============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
kworker/u10:13/18317 is trying to acquire lock:
ffffe8ffffc73b58 (&pd_list->lock){+...}-{3:3}, at: padata_do_serial+0x707/0xb80

but task is already holding lock:
ffffe8ffffc73ba8 (&pd_list->lock){+...}-{3:3}, at: padata_do_serial+0x590/0xb80

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

       CPU0
       ----
  lock(&pd_list->lock);
  lock(&pd_list->lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

12 locks held by kworker/u10:13/18317:
 #0: ffff88816959e948 ((wq_completion)pencrypt_parallel){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90007ea7ba0 ((work_completion)(&pw->pw_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8e13d380 (rcu_read_lock_bh){....}-{1:3}, at: padata_do_parallel+0x4b/0xab0
 #3: ffffffff8e13d380 (rcu_read_lock_bh){....}-{1:3}, at: padata_do_parallel+0x4b/0xab0
 #4: ffffffff8e13d380 (rcu_read_lock_bh){....}-{1:3}, at: padata_do_parallel+0x4b/0xab0
 #5: ffffffff8e13d380 (rcu_read_lock_bh){....}-{1:3}, at: padata_do_parallel+0x4b/0xab0
 #6: ffffffff8e13d380 (rcu_read_lock_bh){....}-{1:3}, at: padata_do_parallel+0x4b/0xab0
 #7: ffffffff8e13d380 (rcu_read_lock_bh){....}-{1:3}, at: padata_do_parallel+0x4b/0xab0
 #8: ffffffff8e13d380 (rcu_read_lock_bh){....}-{1:3}, at: padata_do_parallel+0x4b/0xab0
 #9: ffffffff8e13d380 (rcu_read_lock_bh){....}-{1:3}, at: padata_do_parallel+0x4b/0xab0
 #10: ffffffff8e13d380 (rcu_read_lock_bh){....}-{1:3}, at: padata_do_parallel+0x4b/0xab0
 #11: ffffe8ffffc73ba8 (&pd_list->lock){+...}-{3:3}, at: padata_do_serial+0x590/0xb80

stack backtrace:
CPU: 1 UID: 0 PID: 18317 Comm: kworker/u10:13 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
Workqueue: pencrypt_parallel padata_parallel_worker
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_deadlock_bug+0x28b/0x2a0
 validate_chain+0x1a3f/0x2140
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 _raw_spin_lock+0x2e/0x40
 padata_do_serial+0x707/0xb80
 padata_do_parallel+0x7ba/0xab0
 pcrypt_aead_encrypt+0x2f1/0x400
 pcrypt_aead_enc+0x17/0x80
 padata_do_parallel+0x7ba/0xab0
 pcrypt_aead_encrypt+0x2f1/0x400
 pcrypt_aead_enc+0x17/0x80
 padata_do_parallel+0x7ba/0xab0
 pcrypt_aead_encrypt+0x2f1/0x400
 pcrypt_aead_enc+0x17/0x80
 padata_do_parallel+0x7ba/0xab0
 pcrypt_aead_encrypt+0x2f1/0x400
 pcrypt_aead_enc+0x17/0x80
 padata_do_parallel+0x7ba/0xab0
 pcrypt_aead_encrypt+0x2f1/0x400
 pcrypt_aead_enc+0x17/0x80
 padata_do_parallel+0x7ba/0xab0
 pcrypt_aead_encrypt+0x2f1/0x400
 pcrypt_aead_enc+0x17/0x80
 padata_do_parallel+0x7ba/0xab0
 pcrypt_aead_encrypt+0x2f1/0x400
 pcrypt_aead_enc+0x17/0x80
 padata_do_parallel+0x7ba/0xab0
 pcrypt_aead_encrypt+0x2f1/0x400
 pcrypt_aead_enc+0x17/0x80
 padata_do_parallel+0x7ba/0xab0
 pcrypt_aead_encrypt+0x2f1/0x400
 pcrypt_aead_enc+0x17/0x80
 padata_parallel_worker+0x75/0x1d0
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30
 </TASK>
