------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 7718 at lib/refcount.c:25 refcount_warn_saturate+0xf3/0x1b0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 7718 Comm: syz.3.653 Not tainted 6.6.93-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:refcount_warn_saturate+0xf3/0x1b0 lib/refcount.c:25
Code: 15 0a 01 0f 85 98 00 00 00 e8 39 41 66 fd 5b 41 5e c3 e8 30 41 66 fd c6 05 e1 00 15 0a 01 48 c7 c7 40 0f fc 8a e8 0d a5 30 fd <0f> 0b eb e0 e8 14 41 66 fd c6 05 c6 00 15 0a 01 48 c7 c7 a0 0f fc
RSP: 0018:ffffc90000007848 EFLAGS: 00010246
RAX: facfbf59f1a5f600 RBX: 0000000000000002 RCX: ffff888028de1e00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc900000079d0 R08: ffffc90000007447 R09: 1ffff92000000e88
R10: dffffc0000000000 R11: fffff52000000e89 R12: ffff88807f05ba80
R13: dffffc0000000000 R14: ffff88807f05bbd4 R15: ffff88805eba8800
FS:  00007f81978446c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000140 CR3: 0000000078ae1000 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:261 [inline]
 tipc_aead_encrypt net/tipc/crypto.c:821 [inline]
 tipc_crypto_xmit+0x17cf/0x2250 net/tipc/crypto.c:1761
 tipc_bearer_xmit_skb+0x246/0x3f0 net/tipc/bearer.c:572
 tipc_disc_timeout+0x581/0x6d0 net/tipc/discover.c:338
 call_timer_fn+0x16e/0x530 kernel/time/timer.c:1700
 expire_timers kernel/time/timer.c:1751 [inline]
 __run_timers+0x52d/0x7d0 kernel/time/timer.c:2022
 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2035
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:rcu_lockdep_current_cpu_online+0x6/0x120 kernel/rcu/tree.c:4214
Code: 4c 85 3b 0f 95 c0 5b 41 5e 41 5f c3 89 fe 89 fb 48 c7 c7 00 4c d3 8c e8 78 41 e2 02 89 df e9 53 ff ff ff 90 f3 0f 1e fa 41 57 <41> 56 53 65 8b 0d 08 dc 93 7e b0 01 f7 c1 00 00 f0 00 0f 85 d5 00
RSP: 0018:ffffc90002ee74d8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: facfbf59f1a5f600
RDX: ffff888028de1e00 RSI: ffffffff8afc6760 RDI: ffffffff8afc6720
RBP: 0000000000000000 R08: dffffc0000000000 R09: 1ffffffff21b08a4
R10: dffffc0000000000 R11: fffffbfff21b08a5 R12: ffff8880263e9ed0
R13: ffffc90002ee75d8 R14: ffffc90002ee75c0 R15: 1ffff920005dcebb
 rcu_read_lock_held_common kernel/rcu/update.c:112 [inline]
 rcu_read_lock_held+0x1e/0x40 kernel/rcu/update.c:348
 xa_head include/linux/xarray.h:1200 [inline]
 xas_start+0x292/0x770 lib/xarray.c:190
 xas_load+0x2c/0x140 lib/xarray.c:237
 filemap_get_entry+0x165/0x3c0 mm/filemap.c:1852
 shmem_get_folio_gfp+0x2a5/0x2ac0 mm/shmem.c:1976
 shmem_fault+0x1b6/0x7f0 mm/shmem.c:2249
 __do_fault+0x13b/0x4e0 mm/memory.c:4243
 do_read_fault mm/memory.c:4616 [inline]
 do_fault mm/memory.c:4753 [inline]
 do_pte_missing mm/memory.c:3688 [inline]
 handle_pte_fault mm/memory.c:5025 [inline]
 __handle_mm_fault mm/memory.c:5166 [inline]
 handle_mm_fault+0x3886/0x4920 mm/memory.c:5331
 faultin_page mm/gup.c:868 [inline]
 __get_user_pages+0x5ea/0x1470 mm/gup.c:1167
 populate_vma_page_range+0x2b6/0x370 mm/gup.c:1593
 __mm_populate+0x24c/0x380 mm/gup.c:1696
 mm_populate include/linux/mm.h:3312 [inline]
 vm_mmap_pgoff+0x2e7/0x400 mm/util.c:561
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f819698e929
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:00007f8197844038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f8196bb5fa0 RCX: 00007f819698e929
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007f8196a10b39 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f8196bb5fa0 R15: 00007ffc0f1d3ad8
 </TASK>
----------------
Code disassembly (best guess):
   0:	4c 85 3b             	test   %r15,(%rbx)
   3:	0f 95 c0             	setne  %al
   6:	5b                   	pop    %rbx
   7:	41 5e                	pop    %r14
   9:	41 5f                	pop    %r15
   b:	c3                   	ret
   c:	89 fe                	mov    %edi,%esi
   e:	89 fb                	mov    %edi,%ebx
  10:	48 c7 c7 00 4c d3 8c 	mov    $0xffffffff8cd34c00,%rdi
  17:	e8 78 41 e2 02       	call   0x2e24194
  1c:	89 df                	mov    %ebx,%edi
  1e:	e9 53 ff ff ff       	jmp    0xffffff76
  23:	90                   	nop
  24:	f3 0f 1e fa          	endbr64
  28:	41 57                	push   %r15
* 2a:	41 56                	push   %r14 <-- trapping instruction
  2c:	53                   	push   %rbx
  2d:	65 8b 0d 08 dc 93 7e 	mov    %gs:0x7e93dc08(%rip),%ecx        # 0x7e93dc3c
  34:	b0 01                	mov    $0x1,%al
  36:	f7 c1 00 00 f0 00    	test   $0xf00000,%ecx
  3c:	0f                   	.byte 0xf
  3d:	85 d5                	test   %edx,%ebp