syzbot

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WARNING: CPU: 1 PID: 4528 at kernel/rcu/tree_stall.h:970 rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:962
Modules linked in:
CPU: 1 PID: 4528 Comm: syz.0.54 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:970
Code: ff ff ff 48 c7 c7 20 3f a1 96 be 04 00 00 00 e8 3a 5d 65 00 48 89 df b8 01 00 00 00 87 05 8c 89 35 15 85 c0 0f 85 19 ff ff ff <0f> 0b 48 81 ff 80 06 93 8c 74 47 48 c7 c0 e4 42 ff 8d 48 c1 e8 03
RSP: 0018:ffffc900001e0b78 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffffff8c930680 RCX: ffffffff816bb586
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8c930680
RBP: ffffc900001e0df0 R08: 0000000000000004 R09: 0000000000000003
R10: fffffbfff2d427e4 R11: 1ffffffff2d427e4 R12: 0000000000002904
R13: dffffc0000000000 R14: 0000000000000a06 R15: dffffc0000000000
FS:  00005555874dd500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc088a9ff8 CR3: 000000002e9b8000 CR4: 00000000003506e0
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 ae 05 49 f7 48 89 df e8 06 cb 49 f7 e8 d1 bd 6c f7 fb bf 01 00 00 00 <e8> 96 43 3d f7 65 8b 05 27 f1 e7 75 85 c0 74 02 5b c3 e8 c4 02 e6
RSP: 0018:ffffc90003657b98 EFLAGS: 00000282
RAX: 33973d228fc4e500 RBX: ffff88802eead340 RCX: 33973d228fc4e500
RDX: dffffc0000000000 RSI: ffffffff8a6c0600 RDI: 0000000000000001
RBP: ffff88802eead5d8 R08: dffffc0000000000 R09: ffffed1005dd5a69
R10: ffffed1005dd5a69 R11: 1ffff11005dd5a68 R12: 1ffff11005dd5abb
R13: 0000000000000011 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+0xb7/0x1240 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: 0033:0x7f7aabb84da4
Code: 48 83 c4 18 c3 e8 2c dc 00 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8b 05 71 e9 22 00 48 85 c0 74 14 48 83 ec 08 ff d0 85 c0 <75> 1a 31 c0 48 83 c4 08 c3 0f 1f 00 b8 e4 00 00 00 0f 05 85 c0 75
RSP: 002b:00007ffcc5caf8a0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000000001ff
RDX: 0000010809ed4761 RSI: 00007ffcc5caf900 RDI: 000000001e1eb1da
RBP: 00007f7aabc281eb R08: 00000000000001ff R09: 001dc22174504a08
R10: 000001080921a358 R11: 0000000000013e6e R12: 0000000000000000
R13: 00007f7aabde5fa0 R14: 00007f7aabde5fa0 R15: 0000000000000003
 </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 ae 05 49 f7       	call   0xf74905c3
  15:	48 89 df             	mov    %rbx,%rdi
  18:	e8 06 cb 49 f7       	call   0xf749cb23
  1d:	e8 d1 bd 6c f7       	call   0xf76cbdf3
  22:	fb                   	sti
  23:	bf 01 00 00 00       	mov    $0x1,%edi
* 28:	e8 96 43 3d f7       	call   0xf73d43c3 <-- trapping instruction
  2d:	65 8b 05 27 f1 e7 75 	mov    %gs:0x75e7f127(%rip),%eax        # 0x75e7f15b
  34:	85 c0                	test   %eax,%eax
  36:	74 02                	je     0x3a
  38:	5b                   	pop    %rbx
  39:	c3                   	ret
  3a:	e8                   	.byte 0xe8
  3b:	c4                   	.byte 0xc4
  3c:	02 e6                	add    %dh,%ah