------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 6357 at lib/refcount.c:25 refcount_warn_saturate+0xff/0x1a0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 6357 Comm: syz.4.619 Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:refcount_warn_saturate+0xff/0x1a0 lib/refcount.c:25
Code: 09 01 48 c7 c7 a0 d2 be 8a e8 ad 30 45 fd 0f 0b eb e0 e8 f4 1d 79 fd c6 05 fa 72 e2 09 01 48 c7 c7 e0 d1 be 8a e8 91 30 45 fd <0f> 0b eb c4 e8 d8 1d 79 fd c6 05 df 72 e2 09 01 48 c7 c7 40 d2 be
RSP: 0000:ffffc90000007828 EFLAGS: 00010246
RAX: 3ea9fe8b7469ff00 RBX: 0000000000000002 RCX: ffff888058685940
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc90000007990 R08: dffffc0000000000 R09: fffff52000000e95
R10: fffff52000000e95 R11: 1ffff92000000e94 R12: ffff8880590c1c40
R13: dffffc0000000000 R14: 0000000000000002 R15: ffff888056e8e048
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2da1aff8 CR3: 000000005ca5f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __refcount_add include/linux/refcount.h:-1 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 get_net include/net/net_namespace.h:257 [inline]
 tipc_aead_encrypt net/tipc/crypto.c:821 [inline]
 tipc_crypto_xmit+0x17a9/0x2300 net/tipc/crypto.c:1761
 tipc_bearer_xmit_skb+0x242/0x3f0 net/tipc/bearer.c:574
 tipc_disc_timeout+0x568/0x6b0 net/tipc/discover.c:338
 call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1504
 expire_timers kernel/time/timer.c:1549 [inline]
 __run_timers+0x525/0x7c0 kernel/time/timer.c:1820
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
 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:xas_descend+0x156/0x490 lib/xarray.c:206
Code: ff 89 c6 e8 4c 80 7e f7 85 ed 0f 84 9e 02 00 00 e8 df 7c 7e f7 4c 8d 6b 18 4c 89 e8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ef e8 fc f5 cf f7 4d 89 7d 00 45 89 e5 41
RSP: 0000:ffffc90004676fb8 EFLAGS: 00000a02
RAX: 1ffff920008cee23 RBX: ffffc90004677100 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffff888058685940 R09: 0000000000000002
R10: 0000000000000003 R11: 0000000000000000 R12: ffffea0001122580
R13: ffffc90004677118 R14: 00000000000013b0 R15: ffff88805444a3c0
 xas_load lib/xarray.c:242 [inline]
 xas_find+0x1e0/0xab0 lib/xarray.c:1252
 find_get_entry mm/filemap.c:2031 [inline]
 find_lock_entries+0x1ac/0xb90 mm/filemap.c:2123
 shmem_undo_range+0x227/0x2050 mm/shmem.c:925
 shmem_truncate_range mm/shmem.c:1062 [inline]
 shmem_evict_inode+0x248/0xa40 mm/shmem.c:1171
 evict+0x485/0x870 fs/inode.c:705
 __dentry_kill+0x431/0x650 fs/dcache.c:611
 shrink_dentry_list+0x39b/0x6a0 fs/dcache.c:1206
 shrink_dcache_parent+0xa8/0x3c0 fs/dcache.c:-1
 do_one_tree+0x23/0xe0 fs/dcache.c:1687
 shrink_dcache_for_umount+0x65/0x110 fs/dcache.c:1704
 generic_shutdown_super+0x63/0x340 fs/super.c:473
 kill_anon_super fs/super.c:1128 [inline]
 kill_litter_super+0x72/0xa0 fs/super.c:1137
 deactivate_locked_super+0x93/0xf0 fs/super.c:332
 cleanup_mnt+0x463/0x4f0 fs/namespace.c:1182
 task_work_run+0x1ca/0x250 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0x936/0x2400 kernel/exit.c:871
 do_group_exit+0x217/0x2d0 kernel/exit.c:1021
 get_signal+0x1272/0x1350 kernel/signal.c:2871
 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
 exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1490
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7fb55aa4f837
Code: Unable to access opcode bytes at 0x7fb55aa4f80d.
RSP: 002b:00007fb55a9e0120 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007fb55ab8e929
RDX: 00007fb55a9e0140 RSI: 00007fb55a9e0270 RDI: 000000000000000b
RBP: 00007fb55ac10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fb55adb5fa0 R15: 00007ffdde3fe608
 </TASK>
----------------
Code disassembly (best guess):
   0:	ff 89 c6 e8 4c 80    	decl   -0x7fb3173a(%rcx)
   6:	7e f7                	jle    0xffffffff
   8:	85 ed                	test   %ebp,%ebp
   a:	0f 84 9e 02 00 00    	je     0x2ae
  10:	e8 df 7c 7e f7       	call   0xf77e7cf4
  15:	4c 8d 6b 18          	lea    0x18(%rbx),%r13
  19:	4c 89 e8             	mov    %r13,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 ef             	mov    %r13,%rdi
  33:	e8 fc f5 cf f7       	call   0xf7cff634
  38:	4d 89 7d 00          	mov    %r15,0x0(%r13)
  3c:	45 89 e5             	mov    %r12d,%r13d
  3f:	41                   	rex.B