rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9197/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=337901, q=1981 ncpus=1)
task:syz.8.4965      state:R  running task     stack:26872 pid:9197  tgid:9193  ppid:8724   task_flags:0x400040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 preempt_schedule_irq+0x4b/0x90
 irqentry_exit+0x14f/0x910
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:__task_pid_nr_ns+0x2fb/0x470
Code: e4 00 00 00 e8 e6 11 37 00 e9 32 ff ff ff 4e 8d 34 3b 49 81 c6 f0 00 00 00 e8 d1 11 37 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 4e 01 00 00 41 8b 2e e8 45 d3 53 0a 41 89 c6 31 ff 89
RSP: 0018:ffffc9000397fea8 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: ffff88811661f800 RCX: ffff888161703c00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: 0000000000000001 R08: 1f00000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8ed5c6e0 R12: ffff88811661f908
R13: dffffc0000000000 R14: ffff88811661f900 R15: 0000000000000010
 __ia32_sys_getpid+0x1d/0x30
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fab15197ed7
RSP: 002b:00007fab1601fc48 EFLAGS: 00000206 ORIG_RAX: 0000000000000027
RAX: ffffffffffffffda RBX: 00007fab1601fdb0 RCX: 00007fab15197ed7
RDX: 00007fab1601fc80 RSI: 00007fab1601fdb0 RDI: 0000000000000021
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fab15426218 R14: 00007fffdc903c10 R15: 00007fffdc903cf8
 </TASK>
rcu: rcu_preempt kthread starved for 10502 jiffies! g337901 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27472 pid:17    tgid:17    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 preempt_schedule_common+0x7f/0xd0
 preempt_schedule_thunk+0x16/0x40
 _raw_spin_unlock_irqrestore+0x76/0x80
 __mod_timer+0xb53/0xed0
 schedule_timeout+0x14d/0x2c0
 rcu_gp_fqs_loop+0x30c/0x11f0
 rcu_gp_kthread+0x9e/0x2b0
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 32631 Comm: kworker/u11:0 Tainted: G             L      syzkaller #0 PREEMPT(lazy) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: hci4 hci_conn_timeout
RIP: 0010:finish_task_switch+0x413/0xc60
Code: 04 00 00 41 c7 84 24 20 0e 00 00 00 00 00 00 0f 1f 44 00 00 49 83 c4 48 4c 89 e7 e8 67 36 51 0a e8 e2 00 3a 00 fb 4c 8b 65 c8 <49> 8d bc 24 10 17 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0018:ffffc9000439f5a0 EFLAGS: 00000202
RAX: 000000000012636b RBX: ffff88812103cb20 RCX: 8000000000000001
RDX: 0000000000000007 RSI: ffffffff8e474924 RDI: ffffffff8c6d9c80
RBP: ffffc9000439f5f0 R08: ffffffff907a197f R09: 1ffffffff20f432f
R10: dffffc0000000000 R11: fffffbfff20f4330 R12: ffff888111930000
R13: ffff88812103cae8 R14: dffffc0000000000 R15: 1ffff11024207964
FS:  0000000000000000(0000) GS:ffff88818d6d6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 00000000346b4000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __schedule+0x17e3/0x58f0
 preempt_schedule_common+0x7f/0xd0
 preempt_schedule_thunk+0x16/0x40
 _raw_spin_unlock_irqrestore+0x76/0x80
 __slab_free+0x222/0x2c0
 qlist_free_all+0x99/0x100
 kasan_quarantine_reduce+0x148/0x160
 __kasan_kmalloc+0x22/0xb0
 __kmalloc_cache_noprof+0x321/0x600
 hci_cmd_sync_submit+0xc4/0x2d0
 hci_abort_conn+0x106/0x260
 process_scheduled_works+0xc3d/0x1630
 worker_thread+0xa47/0xfb0
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
