------------[ cut here ]------------
WARNING: kernel/rcu/tree_stall.h:1049 at rcu_check_gp_start_stall.part.0+0x1c4/0x4b0 kernel/rcu/tree_stall.h:1049, CPU#1: syz.8.1491/13862
Modules linked in:
CPU: 1 UID: 0 PID: 13862 Comm: syz.8.1491 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rcu_check_gp_start_stall.part.0+0x1c4/0x4b0 kernel/rcu/tree_stall.h:1049
Code: 88 61 01 00 00 be 04 00 00 00 48 c7 c7 c0 72 c2 9a e8 10 48 84 00 b8 01 00 00 00 87 05 d5 e3 1e 19 85 c0 0f 85 3d 01 00 00 90 <0f> 0b 90 48 c7 c3 54 24 89 90 48 81 fd 80 46 3d 8e 74 5a 48 b8 00
RSP: 0018:ffffc90000a08df0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000002904 RCX: ffffffff81a38ee0
RDX: fffffbfff3584e58 RSI: 0000000000000004 RDI: ffffffff9ac272c0
RBP: ffffffff8e3d4680 R08: 0000000000000001 R09: fffffbfff3584e58
R10: 0000000000000003 R11: ffff888031854830 R12: 1ffffffff1c02250
R13: 0000000000000246 R14: ffffffff8e3d4680 R15: ffff8880b853bd92
FS:  00007fd0293d56c0(0000) GS:ffff8881249f3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 00000000a3ff8000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:1012 [inline]
 rcu_core+0x4cf/0x15f0 kernel/rcu/tree.c:2852
 handle_softirqs+0x219/0x950 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x109/0x170 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+0xa4/0xc0 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 e6 2e 20 f6 48 89 df e8 9e 81 20 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 <bf> 01 00 00 00 e8 65 84 10 f6 65 8b 05 2e 09 39 08 85 c0 74 16 5b
RSP: 0018:ffffc900042b78b8 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffffffff9ae4f100 RCX: 0000000000000007
RDX: 0000000000000000 RSI: ffffffff8daccd5f RDI: ffffffff8bf2b700
RBP: 0000000000000282 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff9088f3d7 R11: ffff888031854830 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff888056c80000
 __debug_check_no_obj_freed lib/debugobjects.c:1108 [inline]
 debug_check_no_obj_freed+0x31f/0x600 lib/debugobjects.c:1129
 free_pages_prepare mm/page_alloc.c:1413 [inline]
 __free_frozen_pages+0x31a/0x1170 mm/page_alloc.c:2943
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4c/0xf0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_noprof+0x25e/0x770 mm/slub.c:5270
 locks_alloc_lock fs/locks.c:275 [inline]
 flock_lock_inode+0xbbb/0x1000 fs/locks.c:1140
 flock_lock_inode_wait fs/locks.c:2138 [inline]
 locks_lock_inode_wait+0x1da/0x490 fs/locks.c:2165
 locks_lock_file_wait include/linux/filelock.h:447 [inline]
 __do_sys_flock+0x446/0x520 fs/locks.c:2233
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd02858f749
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:00007fd0293d5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000049
RAX: ffffffffffffffda RBX: 00007fd0287e6090 RCX: 00007fd02858f749
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000006
RBP: 00007fd028613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd0287e6128 R14: 00007fd0287e6090 R15: 00007ffdf230cb58
 </TASK>
----------------
Code disassembly (best guess):
   0:	f5                   	cmc
   1:	53                   	push   %rbx
   2:	48 8b 74 24 10       	mov    0x10(%rsp),%rsi
   7:	48 89 fb             	mov    %rdi,%rbx
   a:	48 83 c7 18          	add    $0x18,%rdi
   e:	e8 e6 2e 20 f6       	call   0xf6202ef9
  13:	48 89 df             	mov    %rbx,%rdi
  16:	e8 9e 81 20 f6       	call   0xf62081b9
  1b:	f7 c5 00 02 00 00    	test   $0x200,%ebp
  21:	75 23                	jne    0x46
  23:	9c                   	pushf
  24:	58                   	pop    %rax
  25:	f6 c4 02             	test   $0x2,%ah
  28:	75 37                	jne    0x61
* 2a:	bf 01 00 00 00       	mov    $0x1,%edi <-- trapping instruction
  2f:	e8 65 84 10 f6       	call   0xf6108499
  34:	65 8b 05 2e 09 39 08 	mov    %gs:0x839092e(%rip),%eax        # 0x8390969
  3b:	85 c0                	test   %eax,%eax
  3d:	74 16                	je     0x55
  3f:	5b                   	pop    %rbx