syzbot

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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#0: syz.0.17/6054
Modules linked in:
CPU: 0 UID: 0 PID: 6054 Comm: syz.0.17 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 92 c2 9a e8 00 41 85 00 b8 01 00 00 00 87 05 55 f3 1e 19 85 c0 0f 85 3d 01 00 00 90 <0f> 0b 90 48 c7 c3 74 fe 88 90 48 81 fd 80 46 3d 8e 74 5a 48 b8 00
RSP: 0018:ffffc90000007df0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000002904 RCX: ffffffff81a39f60
RDX: fffffbfff3585258 RSI: 0000000000000004 RDI: ffffffff9ac292c0
RBP: ffffffff8e3d4680 R08: 0000000000000001 R09: fffffbfff3585258
R10: 0000000000000003 R11: ffff88807be654b0 R12: 1ffffffff1c02250
R13: 0000000000000246 R14: ffffffff8e3d4680 R15: ffff8880b843bc52
FS:  0000555572a50500(0000) GS:ffff8881248f1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000000b CR3: 0000000073a26000 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:vcpu_enter_guest arch/x86/kvm/x86.c:11448 [inline]
RIP: 0010:vcpu_run+0x3197/0x5a80 arch/x86/kvm/x86.c:11648
Code: b6 04 02 48 89 da 83 e2 07 38 d0 7f 08 84 c0 0f 85 d9 23 00 00 41 c6 86 32 0c 00 00 01 e8 f1 43 85 00 fb 48 8b 95 98 fe ff ff <48> b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 9b 23
RSP: 0018:ffffc90003577a80 EFLAGS: 00000206
RAX: 0000000002cf6709 RBX: ffff88801cb08c32 RCX: 0000000000000006
RDX: ffff88801cb09d08 RSI: ffffffff8dacf6fe RDI: ffffffff8bf2b580
RBP: ffffc90003577c10 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff9088cdd7 R11: 0000000000000000 R12: dffffc0000000000
R13: 0001000000000000 R14: ffff88801cb08000 R15: ffff88801cb08038
 kvm_arch_vcpu_ioctl_run+0xfd3/0x1860 arch/x86/kvm/x86.c:11993
 kvm_vcpu_ioctl+0x76d/0x16d0 virt/kvm/kvm_main.c:4492
 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: 0033:0x7fec1f98f749
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:00007fff00e2df88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fec1fbe5fa0 RCX: 00007fec1f98f749
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00007fec1fa13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fec1fbe5fa0 R14: 00007fec1fbe5fa0 R15: 0000000000000003
 </TASK>
----------------
Code disassembly (best guess):
   0:	b6 04                	mov    $0x4,%dh
   2:	02 48 89             	add    -0x77(%rax),%cl
   5:	da 83 e2 07 38 d0    	fiaddl -0x2fc7f81e(%rbx)
   b:	7f 08                	jg     0x15
   d:	84 c0                	test   %al,%al
   f:	0f 85 d9 23 00 00    	jne    0x23ee
  15:	41 c6 86 32 0c 00 00 	movb   $0x1,0xc32(%r14)
  1c:	01
  1d:	e8 f1 43 85 00       	call   0x854413
  22:	fb                   	sti
  23:	48 8b 95 98 fe ff ff 	mov    -0x168(%rbp),%rdx
* 2a:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax <-- trapping instruction
  31:	fc ff df
  34:	48 c1 ea 03          	shr    $0x3,%rdx
  38:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
  3c:	0f                   	.byte 0xf
  3d:	85                   	.byte 0x85
  3e:	9b                   	fwait
  3f:	23                   	.byte 0x23