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WARNING: kernel/rcu/tree_stall.h:1049 at rcu_check_gp_start_stall.part.0+0x1c4/0x4b0 kernel/rcu/tree_stall.h:1049, CPU#1: vhost-9148/9161
Modules linked in:
CPU: 1 UID: 0 PID: 9161 Comm: vhost-9148 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rcu_check_gp_start_stall.part.0+0x1c4/0x4b0 kernel/rcu/tree_stall.h:1049
Code: 88 61 01 00 00 be 04 00 00 00 48 c7 c7 c0 62 c2 9a e8 30 3d 85 00 b8 01 00 00 00 87 05 d5 c3 1e 19 85 c0 0f 85 3d 01 00 00 90 <0f> 0b 90 48 c7 c3 74 ee 88 90 48 81 fd 80 46 3d 8e 74 5a 48 b8 00
RSP: 0018:ffffc90000a08df0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000002904 RCX: ffffffff81a39ee0
RDX: fffffbfff3584c58 RSI: 0000000000000004 RDI: ffffffff9ac262c0
RBP: ffffffff8e3d4680 R08: 0000000000000001 R09: fffffbfff3584c58
R10: 0000000000000003 R11: ffff88802c310b30 R12: 1ffffffff1c02250
R13: 0000000000000246 R14: ffffffff8e3d4680 R15: ffff8880b853bc52
FS:  00007f908e6b76c0(0000) GS:ffff8881249f4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000002 CR3: 0000000059476000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:1012 [inline]
 rcu_core+0x4cf/0x15f0 kernel/rcu/tree.c:2852
 handle_softirqs+0x219/0x950 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:gup_fast mm/gup.c:3177 [inline]
RIP: 0010:gup_fast_fallback+0xdde/0x2350 mm/gup.c:3213
Code: ff 48 85 db 0f 85 e9 12 00 00 e8 2d 11 b4 ff 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 eb 0b b4 ff 48 85 db 0f 85 b4 13 00 00 <e8> 0d 11 b4 ff 44 8b b4 24 cc 00 00 00 31 ff 48 63 5c 24 68 44 89
RSP: 0018:ffffc90003577860 EFLAGS: 00000287
RAX: 000000000000003c RBX: 0000000000000000 RCX: ffffc9001a493000
RDX: 0000000000100000 RSI: ffffffff820afdb1 RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: ffff88802c310b30 R12: 0000000000000000
R13: 0000000000000fff R14: dffffc0000000000 R15: 0000000000000000
 pin_user_pages_fast+0xa7/0xf0 mm/gup.c:3326
 set_bit_to_user drivers/vhost/vhost.c:2425 [inline]
 log_write+0x267/0x320 drivers/vhost/vhost.c:2451
 log_used.isra.0+0x170/0x1e0 drivers/vhost/vhost.c:2507
 vhost_update_used_flags+0x2ff/0x3d0 drivers/vhost/vhost.c:2582
 vhost_disable_notify drivers/vhost/vhost.c:3263 [inline]
 vhost_disable_notify+0xba/0x1b0 drivers/vhost/vhost.c:3255
 vhost_vsock_handle_tx_kick+0x18e/0xdb0 drivers/vhost/vsock.c:501
 vhost_run_work_list+0x18b/0x230 drivers/vhost/vhost.c:454
 vhost_task_fn+0x165/0x460 kernel/vhost_task.c:49
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
----------------
Code disassembly (best guess):
   0:	ff 48 85             	decl   -0x7b(%rax)
   3:	db 0f                	fisttpl (%rdi)
   5:	85 e9                	test   %ebp,%ecx
   7:	12 00                	adc    (%rax),%al
   9:	00 e8                	add    %ch,%al
   b:	2d 11 b4 ff 9c       	sub    $0x9cffb411,%eax
  10:	5b                   	pop    %rbx
  11:	81 e3 00 02 00 00    	and    $0x200,%ebx
  17:	31 ff                	xor    %edi,%edi
  19:	48 89 de             	mov    %rbx,%rsi
  1c:	e8 eb 0b b4 ff       	call   0xffb40c0c
  21:	48 85 db             	test   %rbx,%rbx
  24:	0f 85 b4 13 00 00    	jne    0x13de
* 2a:	e8 0d 11 b4 ff       	call   0xffb4113c <-- trapping instruction
  2f:	44 8b b4 24 cc 00 00 	mov    0xcc(%rsp),%r14d
  36:	00
  37:	31 ff                	xor    %edi,%edi
  39:	48 63 5c 24 68       	movslq 0x68(%rsp),%rbx
  3e:	44                   	rex.R
  3f:	89                   	.byte 0x89