------------[ cut here ]------------
WARNING: CPU: 0 PID: 7985 at kernel/rcu/tree_stall.h:1001 rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:993
Modules linked in:
CPU: 0 PID: 7985 Comm: syz.0.548 Not tainted 6.6.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:1001
Code: ff ff ff 48 c7 c7 80 c4 ee 96 be 04 00 00 00 e8 7a a8 6c 00 48 89 df b8 01 00 00 00 87 05 bc 98 7e 15 85 c0 0f 85 19 ff ff ff <0f> 0b 48 81 ff 40 54 d3 8c 74 47 48 c7 c0 dc bc 4a 8e 48 c1 e8 03
RSP: 0018:ffffc90000007bb8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffffff8cd35440 RCX: ffffffff81702bb6
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8cd35440
RBP: ffffc90000007e30 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff2ddd890 R12: 0000000000002904
R13: 1ffff110171c7a6a R14: 0000000000000a02 R15: dffffc0000000000
FS:  00007fed80e996c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fed801b6098 CR3: 000000002fbed000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 rcu_core+0x612/0x1720 kernel/rcu/tree.c:2462
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__get_user_nocheck_8+0xd/0x20 arch/x86/lib/getuser.S:143
Code: fa 0f 01 cb 0f ae e8 8b 10 31 c0 0f 01 ca c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 01 cb 0f ae e8 48 8b 10 <31> c0 0f 01 ca c3 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 01 ca
RSP: 0018:ffffc90003787cf8 EFLAGS: 00040203
RAX: 00007fed80e98c68 RBX: 00007fed80e98b38 RCX: ffff88802c119e00
RDX: 0000000000000000 RSI: 00007fed80e98b38 RDI: ffffffffffffffff
RBP: ffffc90003787f10 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: ffffc90003780000
R13: 1ffff920006f0ffe R14: dffffc0000000000 R15: 1ffff920006f0fa8
 __ia32_sys_rt_sigreturn+0x119/0x7b0 arch/x86/kernel/signal_64.c:256
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fed7ff2add9
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25
RSP: 002b:00007fed80e98b40 EFLAGS: 00000246 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007fed801b6098 RCX: 00007fed7ff2add9
RDX: 00007fed80e98b40 RSI: 00007fed80e98c70 RDI: 0000000000000011
RBP: 00007fed801b6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fed801b6128 R14: 00007ffd30d6f920 R15: 00007ffd30d6fa08
 </TASK>
----------------
Code disassembly (best guess):
   0:	fa                   	cli
   1:	0f 01 cb             	stac
   4:	0f ae e8             	lfence
   7:	8b 10                	mov    (%rax),%edx
   9:	31 c0                	xor    %eax,%eax
   b:	0f 01 ca             	clac
   e:	c3                   	ret
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  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:	f3 0f 1e fa          	endbr64
  21:	0f 01 cb             	stac
  24:	0f ae e8             	lfence
  27:	48 8b 10             	mov    (%rax),%rdx
* 2a:	31 c0                	xor    %eax,%eax <-- trapping instruction
  2c:	0f 01 ca             	clac
  2f:	c3                   	ret
  30:	90                   	nop
  31:	90                   	nop
  32:	90                   	nop
  33:	90                   	nop
  34:	90                   	nop
  35:	90                   	nop
  36:	90                   	nop
  37:	90                   	nop
  38:	90                   	nop
  39:	90                   	nop
  3a:	90                   	nop
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	0f 01 ca             	clac