rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (1 GPs behind) idle=1cc4/1/0x4000000000000000 softirq=0/0 fqs=0 rcuc=11768 jiffies(starved)
rcu: 	(t=10500 jiffies g=13025 q=172 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 10372 jiffies! g13025 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=4096
rcu: rcu_preempt kthread starved for 10500 jiffies! g13025 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:27736 pid:18    tgid:18    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f9/0x5500 kernel/sched/core.c:7197
 __schedule_loop kernel/sched/core.c:7276 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7291
 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x312/0x11b0 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
 </TASK>
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: 5823 Comm: vhost-5820 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:__get_user_pages+0x1dc/0x2570 mm/gup.c:-1
Code: b1 ff 44 89 eb 81 e3 00 08 00 00 31 ff 89 de e8 aa 8e b1 ff c1 eb 02 83 cb 14 44 21 f3 09 eb 44 09 fb 89 dd 83 cd 0c 44 89 ee <83> e6 10 0f 44 eb 31 ff e8 87 8e b1 ff 44 89 e8 c1 e8 0c 83 e0 20
RSP: 0018:ffffc90004947530 EFLAGS: 00000206
RAX: ffffffff82134226 RBX: 0000000000000015 RCX: ffff888029321ec0
RDX: 0000000000000000 RSI: 0000000000290001 RDI: 0000000000000000
RBP: 000000000000001d R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1027fce639 R12: dffffc0000000000
R13: 0000000000290001 R14: 00000000ffffffff R15: 0000000000000001
FS:  0000555584ae7400(0000) GS:ffff88812601f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000002 CR3: 000000002507e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __get_user_pages_locked mm/gup.c:1692 [inline]
 __gup_longterm_locked+0xdcf/0x1630 mm/gup.c:2483
 gup_fast_fallback+0x1cfd/0x2040 mm/gup.c:3216
 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
 </TASK>
CPU: 0 UID: 0 PID: 5822 Comm: vhost-5821 Not tainted syzkaller #0 PREEMPT_{RT,(full)}