------------[ cut here ]------------
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: syz.2.1110/10201
Modules linked in:
CPU: 1 UID: 0 PID: 10201 Comm: syz.2.1110 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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 52 c2 9a e8 30 38 85 00 b8 01 00 00 00 87 05 d5 c4 1e 19 85 c0 0f 85 3d 01 00 00 90 <0f> 0b 90 48 c7 c3 74 e6 88 90 48 81 fd 80 46 3d 8e 74 5a 48 b8 00
RSP: 0018:ffffc90000a08df0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000002904 RCX: ffffffff81a38de0
RDX: fffffbfff3584a58 RSI: 0000000000000004 RDI: ffffffff9ac252c0
RBP: ffffffff8e3d4680 R08: 0000000000000001 R09: fffffbfff3584a58
R10: 0000000000000003 R11: ffff88807a7c0b30 R12: 1ffffffff1c02250
R13: 0000000000000246 R14: ffffffff8e3d4680 R15: ffff8880b853bc52
FS:  00007fc6ab9f16c0(0000) GS:ffff8881249f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc6ab9aef98 CR3: 000000003cc59000 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:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:114 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:128 [inline]
RIP: 0010:lock_acquire kernel/locking/lockdep.c:5864 [inline]
RIP: 0010:lock_acquire+0x133/0x330 kernel/locking/lockdep.c:5825
Code: 00 65 8b 05 d7 fa 18 12 85 c0 0f 85 a2 00 00 00 65 48 8b 05 97 b3 18 12 8b 90 2c 0b 00 00 85 d2 0f 85 8c 00 00 00 9c 8f 04 24 <fa> 48 c7 c7 3c e5 bb 8d e8 d0 12 de 09 45 89 e0 89 e9 44 89 ea 65
RSP: 0018:ffffc9000dcb7a40 EFLAGS: 00000246
RAX: ffff88807a7c0000 RBX: ffff88803cc4ef18 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8b7ad25e RDI: ffffed1007989de3
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000013b6b R11: ffff88807a7c0b30 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 move_pages_ptes mm/userfaultfd.c:1361 [inline]
 move_pages+0x2b4c/0x5070 mm/userfaultfd.c:1905
 userfaultfd_move fs/userfaultfd.c:1942 [inline]
 userfaultfd_ioctl+0x607/0x3930 fs/userfaultfd.c:2065
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc6aab8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc6ab9f1038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc6aade5fa0 RCX: 00007fc6aab8f749
RDX: 0000200000000100 RSI: 00000000c028aa05 RDI: 0000000000000007
RBP: 00007fc6aac13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc6aade6038 R14: 00007fc6aade5fa0 R15: 00007ffce0f7cda8
 </TASK>
----------------
Code disassembly (best guess):
   0:	00 65 8b             	add    %ah,-0x75(%rbp)
   3:	05 d7 fa 18 12       	add    $0x1218fad7,%eax
   8:	85 c0                	test   %eax,%eax
   a:	0f 85 a2 00 00 00    	jne    0xb2
  10:	65 48 8b 05 97 b3 18 	mov    %gs:0x1218b397(%rip),%rax        # 0x1218b3af
  17:	12
  18:	8b 90 2c 0b 00 00    	mov    0xb2c(%rax),%edx
  1e:	85 d2                	test   %edx,%edx
  20:	0f 85 8c 00 00 00    	jne    0xb2
  26:	9c                   	pushf
  27:	8f 04 24             	pop    (%rsp)
* 2a:	fa                   	cli <-- trapping instruction
  2b:	48 c7 c7 3c e5 bb 8d 	mov    $0xffffffff8dbbe53c,%rdi
  32:	e8 d0 12 de 09       	call   0x9de1307
  37:	45 89 e0             	mov    %r12d,%r8d
  3a:	89 e9                	mov    %ebp,%ecx
  3c:	44 89 ea             	mov    %r13d,%edx
  3f:	65                   	gs