syzbot

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WARNING: CPU: 0 PID: 4487 at kernel/rcu/tree_stall.h:970 rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:962
Modules linked in:
CPU: 0 PID: 4487 Comm: syz.1.27 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:970
Code: ff ff ff 48 c7 c7 20 df c2 96 be 04 00 00 00 e8 7a 4c 65 00 48 89 df b8 01 00 00 00 87 05 bc 39 57 15 85 c0 0f 85 19 ff ff ff <0f> 0b 48 81 ff 40 01 b3 8c 74 47 48 c7 c0 a4 aa 1f 8e 48 c1 e8 03
RSP: 0018:ffffc90000007b78 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffffff8cb30140 RCX: ffffffff816ba556
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8cb30140
RBP: ffffc90000007df0 R08: 0000000000000004 R09: 0000000000000003
R10: fffffbfff2d85be4 R11: 1ffffffff2d85be4 R12: 0000000000002904
R13: dffffc0000000000 R14: 0000000000000a06 R15: dffffc0000000000
FS:  0000555589ae0500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 000000005c66d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rcu_core+0x5d9/0x16a0 kernel/rcu/tree.c:2552
 handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ee f7 41 f7 48 89 df e8 46 bd 42 f7 e8 71 af 65 f7 fb bf 01 00 00 00 <e8> 96 3a 36 f7 65 8b 05 97 f3 e0 75 85 c0 74 02 5b c3 e8 e4 04 df
RSP: 0018:ffffc90003687bb8 EFLAGS: 00000286
RAX: e721a6dbfc3da600 RBX: ffff88802e350940 RCX: e721a6dbfc3da600
RDX: dffffc0000000000 RSI: ffffffff8a8c0500 RDI: 0000000000000001
RBP: ffff88802e350dd8 R08: dffffc0000000000 R09: ffffed1005c6a129
R10: ffffed1005c6a129 R11: 1ffff11005c6a128 R12: 1ffff11005c6a1bb
R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 get_signal+0x1163/0x1350 kernel/signal.c:2874
 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3a44b8eec9
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:00007ffc28574308 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f3a44de5fa0 RCX: 00007f3a44b8eec9
RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f3a44c11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3a44de5fa0 R14: 00007f3a44de5fa0 R15: 0000000000000004
 </TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	0f 1f 00             	nopl   (%rax)
   3:	53                   	push   %rbx
   4:	48 89 fb             	mov    %rdi,%rbx
   7:	48 83 c7 18          	add    $0x18,%rdi
   b:	48 8b 74 24 08       	mov    0x8(%rsp),%rsi
  10:	e8 ee f7 41 f7       	call   0xf741f803
  15:	48 89 df             	mov    %rbx,%rdi
  18:	e8 46 bd 42 f7       	call   0xf742bd63
  1d:	e8 71 af 65 f7       	call   0xf765af93
  22:	fb                   	sti
  23:	bf 01 00 00 00       	mov    $0x1,%edi
* 28:	e8 96 3a 36 f7       	call   0xf7363ac3 <-- trapping instruction
  2d:	65 8b 05 97 f3 e0 75 	mov    %gs:0x75e0f397(%rip),%eax        # 0x75e0f3cb
  34:	85 c0                	test   %eax,%eax
  36:	74 02                	je     0x3a
  38:	5b                   	pop    %rbx
  39:	c3                   	ret
  3a:	e8                   	.byte 0xe8
  3b:	e4 04                	in     $0x4,%al
  3d:	df                   	.byte 0xdf