------------[ cut here ]------------
WARNING: kernel/rcu/tree_stall.h:1049 at rcu_check_gp_start_stall+0x2e4/0x470 kernel/rcu/tree_stall.h:1049, CPU#1: syz.4.192/6815
Modules linked in:
CPU: 1 UID: 0 PID: 6815 Comm: syz.4.192 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 85 8f 99 be 04 00 00 00 e8 83 8f 7f 00 4c 89 f7 b8 01 00 00 00 87 05 65 f8 e7 17 85 c0 0f 85 17 ff ff ff 90 <0f> 0b 90 48 81 ff 80 6e f4 8d 74 47 48 c7 c0 a0 54 82 8f 48 c1 e8
RSP: 0018:ffffc90000a08d98 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000246 RCX: ffffffff81a78d2d
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8df46e80
RBP: ffffc90000a08f30 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff331f0b4 R12: 0000000000002904
R13: 1ffff110170e771a R14: ffffffff8df46e80 R15: dffffc0000000000
FS:  00007fc7a07d16c0(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000001a9030 CR3: 0000000054b48000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 rcu_core+0x5f5/0x1720 kernel/rcu/tree.c:2852
 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x60/0x150 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:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x17/0xb0 kernel/rcu/tree.c:751
Code: 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 65 ff 05 00 13 d9 10 e8 6b de b2 09 89 c3 <83> f8 08 73 65 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd d0 fd 9a
RSP: 0018:ffffc9001e4078d0 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000080000001
RDX: ffff88802aa80000 RSI: ffffffff8bc083c0 RDI: ffffffff8bc08380
RBP: ffffc9001e407901 R08: ffffffff8f822477 R09: 1ffffffff1f0448e
R10: dffffc0000000000 R11: fffffbfff1f0448f R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000001
 trace_xfs_group_rele fs/xfs/xfs_trace.h:357 [inline]
 xfs_group_rele+0x82/0x200 fs/xfs/libxfs/xfs_group.c:149
 xfs_group_grab_next_mark+0xb8/0x580 fs/xfs/libxfs/xfs_group.c:131
 xfs_perag_grab_next_tag fs/xfs/xfs_icache.c:311 [inline]
 xfs_icwalk fs/xfs/xfs_icache.c:1856 [inline]
 xfs_reclaim_inodes+0x1e2/0x2b0 fs/xfs/xfs_icache.c:1073
 xfs_unmount_flush_inodes+0xc1/0xd0 fs/xfs/xfs_mount.c:626
 xfs_unmountfs+0x152/0x320 fs/xfs/xfs_mount.c:1322
 xfs_fs_put_super+0x65/0x160 fs/xfs/xfs_super.c:1254
 generic_shutdown_super+0x135/0x2c0 fs/super.c:643
 kill_block_super+0x44/0x90 fs/super.c:1722
 xfs_kill_sb+0x15/0x50 fs/xfs/xfs_super.c:2297
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1318
 task_work_run+0x1d4/0x260 kernel/task_work.c:233
 get_signal+0x11ec/0x1340 kernel/signal.c:2807
 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+0x87/0x4e0 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+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc79f990eea
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007fc7a07d0e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffec RBX: 00007fc7a07d0ef0 RCX: 00007fc79f990eea
RDX: 0000200000000040 RSI: 0000200000009780 RDI: 00007fc7a07d0eb0
RBP: 0000200000000040 R08: 00007fc7a07d0ef0 R09: 0000000000000080
R10: 0000000000000080 R11: 0000000000000246 R12: 0000200000009780
R13: 00007fc7a07d0eb0 R14: 0000000000009830 R15: 0000200000000140
 </TASK>
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	00 90 90 90 90 90    	add    %dl,-0x6f6f6f70(%rax)
   8:	90                   	nop
   9:	90                   	nop
   a:	90                   	nop
   b:	90                   	nop
   c:	90                   	nop
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	f3 0f 1e fa          	endbr64
  17:	41 57                	push   %r15
  19:	41 56                	push   %r14
  1b:	53                   	push   %rbx
  1c:	65 ff 05 00 13 d9 10 	incl   %gs:0x10d91300(%rip)        # 0x10d91323
  23:	e8 6b de b2 09       	call   0x9b2de93
  28:	89 c3                	mov    %eax,%ebx
* 2a:	83 f8 08             	cmp    $0x8,%eax <-- trapping instruction
  2d:	73 65                	jae    0x94
  2f:	49 bf 00 00 00 00 00 	movabs $0xdffffc0000000000,%r15
  36:	fc ff df
  39:	4c                   	rex.WR
  3a:	8d                   	.byte 0x8d
  3b:	34 dd                	xor    $0xdd,%al
  3d:	d0 fd                	sar    %ch
  3f:	9a                   	(bad)