------------[ cut here ]------------
WARNING: kernel/rcu/tree_stall.h:1049 at rcu_check_gp_start_stall+0x2e4/0x470 kernel/rcu/tree_stall.h:1049, CPU#0: syz.0.2487/15415
Modules linked in:
CPU: 0 UID: 0 PID: 15415 Comm: syz.0.2487 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+0x2e4/0x470 kernel/rcu/tree_stall.h:1049
Code: ff ff 48 c7 c7 a0 25 8e 99 be 04 00 00 00 e8 63 df 7f 00 4c 89 f7 b8 01 00 00 00 87 05 c5 f3 e5 17 85 c0 0f 85 17 ff ff ff 90 <0f> 0b 90 48 81 ff 00 6e f4 8d 74 47 48 c7 c0 a0 4f 82 8f 48 c1 e8
RSP: 0018:ffffc90000007b78 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000a06 RCX: ffffffff81a831cd
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8df46e00
RBP: ffffc90000007e30 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff331c4b4 R12: 0000000000002904
R13: 1ffff110170c771a R14: ffffffff8df46e00 R15: dffffc0000000000
FS:  00007fd3a32f56c0(0000) GS:ffff888125e35000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000083c0 CR3: 00000000480b0000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000200000000300
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 rcu_core+0x6a9/0x1870 kernel/rcu/tree.c:2852
 handle_softirqs+0x27d/0x850 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x1f0 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+0xa6/0xc0 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:__preempt_count_add kernel/rcu/tree.c:747 [inline]
RIP: 0010:rcu_is_watching+0x6/0xb0 kernel/rcu/tree.c:750
Code: e8 ff 76 20 03 eb cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 <41> 56 53 65 ff 05 c0 14 d7 10 e8 ab 32 b4 09 89 c3 83 f8 08 73 65
RSP: 0018:ffffc9000c24f2d8 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffe8ffffc2f6b0
RDX: 0000000000000000 RSI: ffffffff8bc08340 RDI: ffffffff8bc08300
RBP: ffffffff8233ab68 R08: 0000000000000002 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff94000408d61 R12: 0000000000000002
R13: ffffffff8df41a20 R14: 0000000000000000 R15: 0000000000000000
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0x5f/0x340 kernel/locking/lockdep.c:5831
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 page_table_check_set+0x165/0x610 mm/page_table_check.c:112
 page_table_check_ptes_set include/linux/page_table_check.h:76 [inline]
 set_ptes include/linux/pgtable.h:292 [inline]
 __copy_present_ptes mm/memory.c:1102 [inline]
 copy_present_ptes mm/memory.c:1181 [inline]
 copy_pte_range mm/memory.c:1304 [inline]
 copy_pmd_range+0x4d02/0x7e00 mm/memory.c:1392
 copy_pud_range mm/memory.c:1429 [inline]
 copy_p4d_range mm/memory.c:1453 [inline]
 copy_page_range+0xb88/0x11d0 mm/memory.c:1535
 dup_mmap+0xf4a/0x1b80 mm/mmap.c:1827
 dup_mm kernel/fork.c:1529 [inline]
 copy_mm+0x13c/0x4b0 kernel/fork.c:1581
 copy_process+0x165d/0x3950 kernel/fork.c:2221
 kernel_clone+0x21e/0x820 kernel/fork.c:2651
 __do_sys_clone kernel/fork.c:2792 [inline]
 __se_sys_clone kernel/fork.c:2776 [inline]
 __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2776
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd3a238f749
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:00007fd3a32f4fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fd3a25e5fa0 RCX: 00007fd3a238f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fd3a2413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd3a25e6038 R14: 00007fd3a25e5fa0 R15: 00007ffdb2367d98
 </TASK>
----------------
Code disassembly (best guess):
   0:	e8 ff 76 20 03       	call   0x3207704
   5:	eb cc                	jmp    0xffffffd3
   7:	66 66 66 66 2e 0f 1f 	data16 data16 data16 cs nopw 0x0(%rax,%rax,1)
   e:	84 00 00 00 00 00
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	90                   	nop
  1d:	90                   	nop
  1e:	90                   	nop
  1f:	90                   	nop
  20:	90                   	nop
  21:	90                   	nop
  22:	90                   	nop
  23:	90                   	nop
  24:	f3 0f 1e fa          	endbr64
  28:	41 57                	push   %r15
* 2a:	41 56                	push   %r14 <-- trapping instruction
  2c:	53                   	push   %rbx
  2d:	65 ff 05 c0 14 d7 10 	incl   %gs:0x10d714c0(%rip)        # 0x10d714f4
  34:	e8 ab 32 b4 09       	call   0x9b432e4
  39:	89 c3                	mov    %eax,%ebx
  3b:	83 f8 08             	cmp    $0x8,%eax
  3e:	73 65                	jae    0xa5