rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=8f4c/1/0x4000000000000000 softirq=27847/27848 fqs=0
rcu: 	(t=24001 jiffies g=20961 q=50 ncpus=2)
rcu: rcu_preempt kthread starved for 24001 jiffies! g20961 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:27544 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 schedule+0x164/0x360
 schedule_timeout+0x158/0x2c0
 rcu_gp_fqs_loop+0x312/0x11d0
 rcu_gp_kthread+0x9e/0x2b0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5610 Comm: udevd 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
RIP: 0010:io_serial_in+0x77/0xc0
Code: e8 8e ec 80 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 0f 2a ec fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc900000074f8 EFLAGS: 00000006
RAX: 1ffffffff34f4505 RBX: 00000000000003f9 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffc90000007690 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff8544d4f0 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff9a7a2880 R15: 0000000000000000
FS:  00007fcc88f7e280(0000) GS:ffff88818dc8d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000001711af000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 serial8250_console_write+0x540/0x1ba0
 console_flush_all+0x718/0xb20
 console_unlock+0xd1/0x1c0
 vprintk_emit+0x485/0x560
 _printk+0xdd/0x130
 show_one_workqueue+0x102/0x280
 show_all_workqueues+0x148/0x6d0
 wq_watchdog_timer_fn+0x56f/0x840
 call_timer_fn+0x192/0x5e0
 __run_timer_base+0x652/0x8b0
 run_timer_softirq+0x103/0x170
 handle_softirqs+0x22a/0x840
 __irq_exit_rcu+0xca/0x220
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:lock_acquire+0x221/0x350
Code: ff ff ff e8 e1 11 07 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 cb 7c 97 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 58 61 92
RSP: 0018:ffffc900044ef770 EFLAGS: 00000282
RAX: c5bee82ea016f700 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 000000005a44979c RSI: ffffffff8e219b45 RDI: ffffffff8c28af60
RBP: ffffffff826fca5c R08: ffffffff826fca5c R09: ffffffff8e95cd60
R10: ffff8881154f1de0 R11: ffffffff826fddf0 R12: 0000000000000002
R13: ffffffff8e95cd60 R14: 0000000000000000 R15: 0000000000000246
 kernfs_root+0x38/0x230
 kernfs_iop_permission+0x6c/0x430
 inode_permission+0x46f/0x5f0
 link_path_walk+0xaad/0x18d0
 path_openat+0x2c3/0x3860
 do_file_open+0x23e/0x4a0
 do_sys_openat2+0x113/0x200
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcc88b169a4
Code: 24 20 48 8d 44 24 30 48 89 44 24 28 64 8b 04 25 18 00 00 00 85 c0 75 2c 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 60 48 8b 15 55 a4 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffd3bc66340 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007fcc88b169a4
RDX: 0000000000080000 RSI: 00007ffd3bc66478 RDI: 00000000ffffff9c
RBP: 00007ffd3bc66478 R08: 0000000000000008 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000080000
R13: 000055f6d99f8b42 R14: 0000000000000001 R15: 000055f6d9a14160
 </TASK>
CPU: 1 UID: 0 PID: 6987 Comm: syz.0.308 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
RIP: 0010:preempt_schedule_irq+0x48/0xa0
Code: 49 be 00 00 00 00 00 fc ff df eb 09 48 f7 03 10 00 00 00 74 53 bf 01 00 00 00 e8 a3 dc e9 f5 e8 3e f3 23 f6 fb bf 01 00 00 00 <e8> 53 a2 ff ff 9c 58 fa a9 00 02 00 00 74 05 e8 04 f5 23 f6 bf 01
RSP: 0018:ffffc90007e26d50 EFLAGS: 00000206
RAX: 00000000002c93db RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000007 RSI: ffffffff8dfa6837 RDI: 0000000000000001
RBP: 0000000000000000 R08: ffffffff9030b6f7 R09: 1ffffffff20616de
R10: dffffc0000000000 R11: fffffbfff20616df R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000000
FS:  00007f7adc4696c0(0000) GS:ffff8882a928d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000116072000 CR4: 0000000000352ef0
DR0: 000000000000000f DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 irqentry_exit+0x14f/0x760
 asm_sysvec_call_function_single+0x1a/0x20
RIP: 0010:vmx_read_guest_seg_base+0x384/0x580
Code: 48 8d 9b 24 b1 c4 8b 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 0f 85 82 01 00 00 8b 1b 41 0f 78 de <0f> 86 d4 01 00 00 e8 81 ed 69 00 4c 89 f8 48 c1 e8 03 48 b9 00 00
RSP: 0018:ffffc90007e26e70 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 0000000000006808 RCX: dffffc0000000000
RDX: ffffc90008809000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: 0000000000000000 R08: ffff88810ae85617 R09: 1ffff110215d0ac2
R10: dffffc0000000000 R11: ffffed10215d0ac3 R12: ffff88810ae876c0
R13: 1ffff110215d0ed8 R14: 0000000000000000 R15: ffff88810ae876e8
 __do_insn_fetch_bytes+0x38f/0x700
 x86_decode_insn+0x38e/0x5df0
 x86_emulate_instruction+0x64a/0x2100
 kvm_mmu_page_fault+0x91a/0xb70
 vmx_handle_exit+0xd70/0x16f0
 vcpu_run+0x5c77/0x7860
 kvm_arch_vcpu_ioctl_run+0x11e6/0x20d0
 kvm_vcpu_ioctl+0xa62/0xfd0
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7adb59cdd9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7adc469028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7adb815fa0 RCX: 00007f7adb59cdd9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000007
RBP: 00007f7adb632d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7adb816038 R14: 00007f7adb815fa0 R15: 00007ffd6b822268
 </TASK>
  pwq 9: cpus=0-1 node=0 flags=0x4 nice=0 active=6 refcnt=7
    pending: toggle_allocation_gate, 2*nsim_dev_trap_report_work, crng_reseed, 2*cfg80211_wiphy_work
workqueue events_power_efficient: flags=0x180
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=3 refcnt=4
    pending: neigh_managed_work, do_cache_clean, neigh_periodic_work
  pwq 6: cpus=1 node=1 flags=0x0 nice=0 active=4 refcnt=5
    in-flight: 5414:neigh_periodic_work for 0s
    pending: 2*check_lifetime, gc_worker
workqueue events_freezable_pwr_efficient: flags=0x184
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: disk_events_workfn
workqueue rcu_gp: flags=0x108
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=3 refcnt=4
    in-flight: 5668:srcu_invoke_callbacks for 240s
    pending: 2*srcu_invoke_callbacks
workqueue kvfree_rcu_reclaim: flags=0xa
workqueue mm_percpu_wq: flags=0x108
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: vmstat_update
workqueue kblockd: flags=0x118
  pwq 3: cpus=0 node=0 flags=0x0 nice=-20 active=1 refcnt=2
    pending: blk_mq_timeout_work
workqueue hci0: flags=0x20012
  pwq 11: cpus=0-1 flags=0x4 nice=-20 active=1 refcnt=4
    in-flight: 5604:hci_cmd_sync_work for 0s
workqueue hci1: flags=0x20012
  pwq 11: cpus=0-1 flags=0x4 nice=-20 active=1 refcnt=4
    in-flight: 5605:hci_cmd_sync_work for 0s
workqueue hci2: flags=0x20012
  pwq 11: cpus=0-1 flags=0x4 nice=-20 active=1 refcnt=4
    in-flight: 5600:hci_cmd_sync_work for 0s
workqueue wg-kex-wg0: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg1: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg2: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-crypt-wg2: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_tx_worker
workqueue wg-kex-wg0: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg1: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg2: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg0: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-crypt-wg0: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_encrypt_worker
workqueue wg-kex-wg1: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg2: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue hci3: flags=0x20012
  pwq 11: cpus=0-1 flags=0x6 nice=-20 active=1 refcnt=4
    in-flight: 54:hci_power_on for 0s
pool 2: cpus=0 node=0 flags=0x0 nice=0 hung=240s workers=6 idle: 10 797 5682 5679 9
pool 6: cpus=1 node=1 flags=0x0 nice=0 hung=0s workers=6 idle: 5414 5659 24 5660 1287
pool 10: cpus=0-1 node=1 flags=0x4 nice=0 hung=0s workers=5 idle: 27 1195 33 1218
pool 11: cpus=0-1 flags=0x6 nice=-20 hung=0s workers=5 manager: 4998
Showing backtraces of busy workers in stalled worker pools:
pool 2:
task:kworker/0:3     state:R  running task     stack:24376 pid:5668  tgid:5668  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: rcu_gp srcu_invoke_callbacks
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 preempt_schedule_common+0x82/0xd0
 preempt_schedule_thunk+0x16/0x30
 __local_bh_enable_ip+0xe1/0x130
 srcu_invoke_callbacks+0x25b/0x5a0
 process_scheduled_works+0xb5d/0x1860
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
