rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9/4:b..l P1863/2:b..l P5800/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=13161, q=462 ncpus=2)
task:kworker/0:6 state:R running task stack:26504 pid:5800 tgid:5800 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: wg-crypt-wg0 wg_packet_tx_worker
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1681/0x54c0 kernel/sched/core.c:7189
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7370
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
rt_mutex_wake_up_q kernel/locking/rtmutex.c:581 [inline]
__rwbase_read_unlock+0x211/0x250 kernel/locking/rwbase_rt.c:171
read_unlock_bh include/linux/rwlock_rt.h:72 [inline]
wg_socket_send_skb_to_peer+0x18c/0x200 drivers/net/wireguard/socket.c:183
wg_packet_create_data_done drivers/net/wireguard/send.c:251 [inline]
wg_packet_tx_worker+0x1c8/0x7c0 drivers/net/wireguard/send.c:276
process_one_work kernel/workqueue.c:3302 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
task:kworker/0:3 state:R running task stack:21440 pid:1863 tgid:1863 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: wg-crypt-wg0 wg_packet_tx_worker
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1681/0x54c0 kernel/sched/core.c:7189
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline]
irqentry_exit+0x14f/0x730 kernel/entry/common.c:164
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:sched_balance_rq+0x41d4/0x5830 kernel/sched/fair.c:12170
Code: c3 00 02 00 00 74 05 e8 8a 13 34 00 9c 58 a9 00 02 00 00 0f 85 f6 00 00 00 f7 c3 00 02 00 00 74 01 fb 44 8b b4 24 60 03 00 00 <41> f6 c6 02 0f 85 dd ee ff ff 41 f6 c6 04 48 8b 9c 24 18 01 00 00
RSP: 0000:ffffc9000611f4a0 EFLAGS: 00000206
RAX: 0000000000000006 RBX: 0000000000000202 RCX: 0000000000000046
RDX: 0000000000000002 RSI: ffffffff8d604294 RDI: ffffffff8ba74de0
RBP: ffffc9000611f8a8 R08: ffffffff8f88e1f7 R09: 1ffffffff1f11c3e
R10: dffffc0000000000 R11: fffffbfff1f11c3f R12: ffff8880b883c648
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b883c660
sched_balance_domains+0x40f/0x900 kernel/sched/fair.c:12595
handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
__local_bh_enable_ip+0x170/0x2b0 kernel/softirq.c:302
local_bh_enable include/linux/bottom_half.h:33 [inline]
read_unlock_bh include/linux/rwlock_rt.h:73 [inline]
wg_socket_send_skb_to_peer+0x199/0x200 drivers/net/wireguard/socket.c:183
wg_packet_create_data_done drivers/net/wireguard/send.c:251 [inline]
wg_packet_tx_worker+0x1c8/0x7c0 drivers/net/wireguard/send.c:276
process_one_work kernel/workqueue.c:3302 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
task:kworker/0:0 state:R running task stack:22112 pid:9 tgid:9 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: wg-crypt-wg1 wg_packet_tx_worker
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1681/0x54c0 kernel/sched/core.c:7189
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7370
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
rt_mutex_wake_up_q kernel/locking/rtmutex.c:581 [inline]
rt_mutex_slowunlock+0x681/0x8b0 kernel/locking/rtmutex.c:1478
spin_unlock_irqrestore include/linux/spinlock_rt.h:129 [inline]
backlog_unlock_irq_restore net/core/dev.c:255 [inline]
enqueue_to_backlog+0x340/0xcb0 net/core/dev.c:5407
netif_rx_internal+0x120/0x560 net/core/dev.c:5719
__netif_rx+0xa9/0x110 net/core/dev.c:5739
loopback_xmit+0x43a/0x660 drivers/net/loopback.c:90
__netdev_start_xmit include/linux/netdevice.h:5368 [inline]
netdev_start_xmit include/linux/netdevice.h:5377 [inline]
xmit_one net/core/dev.c:3888 [inline]
dev_hard_start_xmit+0x2df/0x860 net/core/dev.c:3904
__dev_queue_xmit+0x1428/0x3900 net/core/dev.c:4870
dev_queue_xmit include/linux/netdevice.h:3418 [inline]
neigh_hh_output include/net/neighbour.h:540 [inline]
neigh_output include/net/neighbour.h:554 [inline]
ip_finish_output2+0xcab/0x10b0 net/ipv4/ip_output.c:237
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip_output+0x29f/0x450 net/ipv4/ip_output.c:438
iptunnel_xmit+0x654/0xda0 net/ipv4/ip_tunnel_core.c:97
udp_tunnel_xmit_skb+0x2b8/0x410 net/ipv4/udp_tunnel_core.c:193
send4+0xa50/0xed0 drivers/net/wireguard/socket.c:85
wg_socket_send_skb_to_peer+0xe8/0x200 drivers/net/wireguard/socket.c:174
wg_packet_create_data_done drivers/net/wireguard/send.c:251 [inline]
wg_packet_tx_worker+0x1c8/0x7c0 drivers/net/wireguard/send.c:276
process_one_work kernel/workqueue.c:3302 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g13161 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=1 timer-softirq=3510
rcu: rcu_preempt kthread starved for 10502 jiffies! g13161 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
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:I stack:27704 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1681/0x54c0 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7283
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5958 Comm: vhost-5956 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:check_preemption_disabled+0x29/0xe0 lib/smp_processor_id.c:19
Code: 90 55 41 57 41 56 53 65 8b 05 a7 ef 4d 07 65 8b 0d 9c ef 4d 07 f7 c1 ff ff ff 7f 74 0c 5b 41 5e 41 5f 5d c3 cc cc cc cc cc 9c <59> f7 c1 00 02 00 00 74 ea 65 4c 8b 3d 4e ef 4d 07 41 f6 47 2f 04
RSP: 0018:ffffc9000594f218 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 00000000ffffffff RCX: 0000000080000000
RDX: ffffc9001b796000 RSI: ffffffff8d61d465 RDI: ffffffff8ba74de0
RBP: 00000000ffffffff R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000004 R12: 0000000000000246
R13: ffff8880272f3d80 R14: ffff88803317d1b0 R15: 0000000000000000
FS: 00007f37cb0966c0(0000) GS:ffff888126279000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32620ff8 CR3: 000000003c3b6000 CR4: 00000000003526f0
Call Trace:
lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline]
lock_is_held_type+0x5a/0x150 kernel/locking/lockdep.c:5939
lock_is_held include/linux/lockdep.h:249 [inline]
mt_locked lib/maple_tree.c:-1 [inline]
mt_slot lib/maple_tree.c:715 [inline]
mtree_range_walk+0x561/0x8b0 lib/maple_tree.c:2050
mas_state_walk lib/maple_tree.c:2952 [inline]
mt_find+0x25f/0x630 lib/maple_tree.c:6271
find_vma+0xed/0x160 mm/mmap.c:908
gup_vma_lookup mm/gup.c:1275 [inline]
__get_user_pages+0x39d/0x2570 mm/gup.c:1396
__get_user_pages_locked mm/gup.c:1692 [inline]
__gup_longterm_locked+0xdcf/0x1630 mm/gup.c:2476
gup_fast_fallback+0x1cf3/0x2040 mm/gup.c:3209
set_bit_to_user drivers/vhost/vhost.c:2420 [inline]
log_write+0xd0/0x6d0 drivers/vhost/vhost.c:2446
vhost_update_used_flags+0x1ed/0x2b0 drivers/vhost/vhost.c:2577
vhost_enable_notify+0xb9/0x650 drivers/vhost/vhost.c:3222
vhost_vsock_handle_tx_kick+0x2ea/0x10a0 drivers/vhost/vsock.c:544
vhost_run_work_list+0x14d/0x1e0 drivers/vhost/vhost.c:454
vhost_task_fn+0x2ef/0x4a0 kernel/vhost_task.c:49
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245