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WARNING: kernel/rcu/tree_stall.h:1049 at rcu_check_gp_start_stall+0x2e4/0x470 kernel/rcu/tree_stall.h:1049, CPU#0: syz.4.445/8236
Modules linked in:
CPU: 0 UID: 0 PID: 8236 Comm: syz.4.445 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:rcu_check_gp_start_stall+0x2e4/0x470 kernel/rcu/tree_stall.h:1049
Code: ff ff 48 c7 c7 c0 25 2b 9a be 04 00 00 00 e8 d3 7c 84 00 4c 89 f7 b8 01 00 00 00 87 05 15 ef 7f 18 85 c0 0f 85 17 ff ff ff 90 <0f> 0b 90 48 81 ff 00 5e 76 8e 74 47 48 c7 c0 c0 b0 11 90 48 c1 e8
RSP: 0018:ffffc90000007db8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000246 RCX: ffffffff81ab369d
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8e765e00
RBP: ffffc90000007f28 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff34564b8 R12: 0000000000002904
R13: dffffc0000000000 R14: ffffffff8e765e00 R15: dffffc0000000000
FS:  00007fc56a9206c0(0000) GS:ffff888125467000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000008f030 CR3: 000000007a60e000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 rcu_core+0x3fe/0x1070 kernel/rcu/tree.c:2864
 handle_softirqs+0x22a/0x870 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x5f/0x150 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:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xce5/0x12c0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 74 e2 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 1f de 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 03 de
RSP: 0018:ffffc900052770e0 EFLAGS: 00000246
RAX: ffffffff81b9ad7d RBX: 1ffff110170e812d RCX: 0000000000080000
RDX: ffffc9000e505000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc90005277210 R08: ffffffff90117db7 R09: 1ffffffff2022fb6
R10: dffffc0000000000 R11: fffffbfff2022fb7 R12: ffff8880b8740968
R13: dffffc0000000000 R14: ffff8880b863bf80 R15: 0000000000000001
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:57 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
 flush_tlb_mm_range+0x5c3/0x10c0 arch/x86/mm/tlb.c:1472
 flush_tlb_page arch/x86/include/asm/tlbflush.h:323 [inline]
 ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:103
 wp_page_copy mm/memory.c:3846 [inline]
 do_wp_page+0x4129/0x5a00 mm/memory.c:4241
 handle_pte_fault mm/memory.c:6332 [inline]
 __handle_mm_fault mm/memory.c:6454 [inline]
 handle_mm_fault+0x1520/0x3310 mm/memory.c:6623
 do_user_addr_fault+0x75b/0x1340 arch/x86/mm/fault.c:1385
 handle_page_fault arch/x86/mm/fault.c:1474 [inline]
 exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0010:__put_user_nocheck_4+0x3/0x10 arch/x86/lib/putuser.S:104
Code: d9 0f 01 cb 89 01 31 c9 0f 01 ca c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 01 cb <89> 01 31 c9 0f 01 ca e9 d1 75 03 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900052778b8 EFLAGS: 00050202
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000020000008f030
RDX: ffff88807b451e40 RSI: 0000000000000002 RDI: 00000000ffffffff
RBP: ffffc90005277a30 R08: ffffc90005277687 R09: 1ffff92000a4eed0
R10: dffffc0000000000 R11: fffff52000a4eed1 R12: 1ffff92000a4ef24
R13: 0000000000000002 R14: 000020000008f000 R15: dffffc0000000000
 ____sys_recvmsg+0x2be/0x4a0 net/socket.c:2825
 ___sys_recvmsg+0x215/0x590 net/socket.c:2854
 do_recvmmsg+0x334/0x800 net/socket.c:2949
 __sys_recvmmsg net/socket.c:3023 [inline]
 __do_sys_recvmmsg net/socket.c:3046 [inline]
 __se_sys_recvmmsg net/socket.c:3039 [inline]
 __x64_sys_recvmmsg+0x198/0x250 net/socket.c:3039
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc56999c629
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc56a920028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007fc569c16090 RCX: 00007fc56999c629
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004
RBP: 00007fc569a32b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc569c16128 R14: 00007fc569c16090 R15: 00007fc569d3fa48
 </TASK>
----------------
Code disassembly (best guess):
   0:	45 8b 2c 24          	mov    (%r12),%r13d
   4:	44 89 ee             	mov    %r13d,%esi
   7:	83 e6 01             	and    $0x1,%esi
   a:	31 ff                	xor    %edi,%edi
   c:	e8 74 e2 0b 00       	call   0xbe285
  11:	41 83 e5 01          	and    $0x1,%r13d
  15:	49 bd 00 00 00 00 00 	movabs $0xdffffc0000000000,%r13
  1c:	fc ff df
  1f:	75 07                	jne    0x28
  21:	e8 1f de 0b 00       	call   0xbde45
  26:	eb 38                	jmp    0x60
  28:	f3 90                	pause
* 2a:	42 0f b6 04 2b       	movzbl (%rbx,%r13,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	75 11                	jne    0x44
  33:	41 f7 04 24 01 00 00 	testl  $0x1,(%r12)
  3a:	00
  3b:	74 1e                	je     0x5b
  3d:	e8                   	.byte 0xe8
  3e:	03 de                	add    %esi,%ebx