------------[ 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.2.1127/10545
Modules linked in:
CPU: 0 UID: 0 PID: 10545 Comm: syz.2.1127 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 50 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:  0000000000000000(0000) GS:ffff888125e35000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f93791b0d58 CR3: 0000000067f4e000 CR4: 00000000003526f0
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:check_kcov_mode kernel/kcov.c:194 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x70 kernel/kcov.c:217
Code: 08 b0 7e 92 65 8b 15 c8 fd bc 10 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 6c 16 00 00 00 74 2c 8b 91 48 16 00 00 <83> fa 02 75 21 48 8b 91 50 16 00 00 48 8b 32 48 8d 7e 01 8b 89 4c
RSP: 0018:ffffc9000f6c7458 EFLAGS: 00000246
RAX: ffffffff81b61c77 RBX: 1ffff110170e8129 RCX: ffff888021bf9e80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000f6c75e0 R08: ffff88801f3e0b87 R09: 1ffff11003e7c170
R10: dffffc0000000000 R11: ffffed1003e7c171 R12: ffff8880b8740948
R13: dffffc0000000000 R14: ffff8880b863bb00 R15: 0000000000000001
 csd_lock_wait kernel/smp.c:342 [inline]
 smp_call_function_many_cond+0xce7/0x12b0 kernel/smp.c:877
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
 flush_tlb_mm_range+0x6b1/0x1280 arch/x86/mm/tlb.c:1472
 tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline]
 tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
 exit_mmap+0x439/0xb10 mm/mmap.c:1290
 __mmput+0x118/0x430 kernel/fork.c:1173
 exit_mm+0x1da/0x2c0 kernel/exit.c:581
 do_exit+0x658/0x2310 kernel/exit.c:959
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2d0/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcbc1b8f749
Code: Unable to access opcode bytes at 0x7fcbc1b8f71f.
RSP: 002b:00007fcbc2a10038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: 0000000000000000 RBX: 00007fcbc1de6090 RCX: 00007fcbc1b8f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006a040000
RBP: 00007fcbc1c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcbc1de6128 R14: 00007fcbc1de6090 R15: 00007ffd7f781898
 </TASK>
----------------
Code disassembly (best guess):
   0:	08 b0 7e 92 65 8b    	or     %dh,-0x749a6d82(%rax)
   6:	15 c8 fd bc 10       	adc    $0x10bcfdc8,%eax
   b:	81 e2 00 01 ff 00    	and    $0xff0100,%edx
  11:	74 11                	je     0x24
  13:	81 fa 00 01 00 00    	cmp    $0x100,%edx
  19:	75 35                	jne    0x50
  1b:	83 b9 6c 16 00 00 00 	cmpl   $0x0,0x166c(%rcx)
  22:	74 2c                	je     0x50
  24:	8b 91 48 16 00 00    	mov    0x1648(%rcx),%edx
* 2a:	83 fa 02             	cmp    $0x2,%edx <-- trapping instruction
  2d:	75 21                	jne    0x50
  2f:	48 8b 91 50 16 00 00 	mov    0x1650(%rcx),%rdx
  36:	48 8b 32             	mov    (%rdx),%rsi
  39:	48 8d 7e 01          	lea    0x1(%rsi),%rdi
  3d:	8b                   	.byte 0x8b
  3e:	89                   	.byte 0x89
  3f:	4c                   	rex.WR