------------[ cut here ]------------
WARNING: CPU: 0 PID: 8640 at fs/namespace.c:163 mnt_ns_release+0x15d/0x1c0 fs/namespace.c:163
Modules linked in:
CPU: 0 UID: 0 PID: 8640 Comm: syz.5.436 Not tainted 6.13.0-rc3-next-20241220-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:mnt_ns_release+0x15d/0x1c0 fs/namespace.c:163
Code: 15 bf 01 00 00 00 89 ee e8 d0 e8 7d ff 85 ed 7e 39 e8 87 e4 7d ff 4c 89 ff 5b 41 5e 41 5f 5d e9 39 be d8 ff e8 74 e4 7d ff 90 <0f> 0b 90 e9 12 ff ff ff e8 66 e4 7d ff 48 89 df be 03 00 00 00 5b
RSP: 0018:ffffc90000007bb8 EFLAGS: 00010246
RAX: ffffffff82413fac RBX: 0000000000000001 RCX: ffff8880304bda00
RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffffc90000007e10 R08: ffffffff82413eb2 R09: 1ffffffff285af0b
R10: dffffc0000000000 R11: ffffffff82424530 R12: ffffffff81a6a6d7
R13: ffff888048d60658 R14: dffffc0000000000 R15: ffff888048d60600
FS:  00007fb5dd74c6c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb5dc969160 CR3: 000000007db66000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rcu_do_batch kernel/rcu/tree.c:2546 [inline]
 rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2802
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
 __do_softirq kernel/softirq.c:595 [inline]
 invoke_softirq kernel/softirq.c:435 [inline]
 __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__rb_change_child include/linux/rbtree_augmented.h:199 [inline]
RIP: 0010:__rb_erase_augmented include/linux/rbtree_augmented.h:242 [inline]
RIP: 0010:rb_erase+0x12c/0xe70 lib/rbtree.c:443
Code: e8 c9 9a 38 f6 4c 8b 33 4c 89 f5 4c 8b 7c 24 20 48 83 e5 fc 74 2e 4c 89 34 24 4c 8d 75 10 4c 89 f0 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 f7 e8 9a 9a 38 f6 4c 8d 7d 08 48 39 5d 10 4d 0f 44 fe
RSP: 0018:ffffc900056efc60 EFLAGS: 00000246
RAX: 1ffff110091dc4d8 RBX: ffff888048d60ab0 RCX: dffffc0000000000
RDX: dffffc0000000000 RSI: ffffffff9a4521a0 RDI: ffff888048d60ab8
RBP: ffff888048ee26b0 R08: ffffffff942d7857 R09: 1ffffffff285af0a
R10: dffffc0000000000 R11: fffffbfff285af0b R12: 0000000000000000
R13: dffffc0000000000 R14: ffff888048ee26c0 R15: ffffffff9a4521a0
 mnt_ns_tree_remove fs/namespace.c:183 [inline]
 free_mnt_ns+0x10f/0x210 fs/namespace.c:3916
 create_new_namespaces+0x6b6/0x7b0 kernel/nsproxy.c:141
 unshare_nsproxy_namespaces+0x124/0x180 kernel/nsproxy.c:228
 ksys_unshare+0x57d/0xa70 kernel/fork.c:3331
 __do_sys_unshare kernel/fork.c:3402 [inline]
 __se_sys_unshare kernel/fork.c:3400 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:3400
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb5dc985d29
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:00007fb5dd74c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fb5dcb75fa0 RCX: 00007fb5dc985d29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000022020600
RBP: 00007fb5dca01b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fb5dcb75fa0 R15: 00007ffd44b5f238
 </TASK>
----------------
Code disassembly (best guess):
   0:	e8 c9 9a 38 f6       	call   0xf6389ace
   5:	4c 8b 33             	mov    (%rbx),%r14
   8:	4c 89 f5             	mov    %r14,%rbp
   b:	4c 8b 7c 24 20       	mov    0x20(%rsp),%r15
  10:	48 83 e5 fc          	and    $0xfffffffffffffffc,%rbp
  14:	74 2e                	je     0x44
  16:	4c 89 34 24          	mov    %r14,(%rsp)
  1a:	4c 8d 75 10          	lea    0x10(%rbp),%r14
  1e:	4c 89 f0             	mov    %r14,%rax
  21:	48 c1 e8 03          	shr    $0x3,%rax
  25:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
* 2a:	74 08                	je     0x34 <-- trapping instruction
  2c:	4c 89 f7             	mov    %r14,%rdi
  2f:	e8 9a 9a 38 f6       	call   0xf6389ace
  34:	4c 8d 7d 08          	lea    0x8(%rbp),%r15
  38:	48 39 5d 10          	cmp    %rbx,0x10(%rbp)
  3c:	4d 0f 44 fe          	cmove  %r14,%r15