------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x111/0x130 lib/refcount.c:25, CPU#0: syz.0.789/9237
Modules linked in:
CPU: 0 UID: 0 PID: 9237 Comm: syz.0.789 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:refcount_warn_saturate+0x111/0x130 lib/refcount.c:25
Code: fb e8 c3 dd ed fc 48 8d 3d 3c 71 10 0c 67 48 0f b9 3a e8 b2 dd ed fc 5b 5d e9 f6 ca f3 fb e8 a6 dd ed fc 48 8d 3d 2f 71 10 0c <67> 48 0f b9 3a e8 95 dd ed fc 5b 5d e9 d9 ca f3 fb 48 89 df e8 c6
RSP: 0018:ffffc900056f7c90 EFLAGS: 00010283
RAX: 000000000000121f RBX: ffff888075a2291c RCX: ffffc90007c01000
RDX: 0000000000080000 RSI: ffffffff851c761a RDI: ffffffff912ce750
RBP: 0000000000000002 R08: 0000000000000005 R09: 0000000000000004
R10: 0000000000000002 R11: 0000000000000000 R12: ffff888075a2291c
R13: ffff8880519af9d8 R14: ffffc900056f7d40 R15: ffff88804e80e000
FS:  00007f4bf4edf6c0(0000) GS:ffff888123ded000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2ef30d CR3: 0000000068ebb000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 __refcount_add include/linux/refcount.h:289 [inline]
 __refcount_inc include/linux/refcount.h:366 [inline]
 refcount_inc include/linux/refcount.h:383 [inline]
 kref_get include/linux/kref.h:45 [inline]
 config_item_get fs/configfs/item.c:104 [inline]
 config_item_get+0x8c/0xb0 fs/configfs/item.c:101
 configfs_get_config_item fs/configfs/configfs_internal.h:127 [inline]
 get_target fs/configfs/symlink.c:128 [inline]
 configfs_symlink+0x390/0x11f0 fs/configfs/symlink.c:185
 vfs_symlink fs/namei.c:5660 [inline]
 vfs_symlink+0x178/0x4d0 fs/namei.c:5639
 filename_symlinkat+0x2a6/0x560 fs/namei.c:5685
 __do_sys_symlinkat fs/namei.c:5705 [inline]
 __se_sys_symlinkat fs/namei.c:5700 [inline]
 __x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5700
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4bf3f9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4bf4edf028 EFLAGS: 00000246 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 00007f4bf4226090 RCX: 00007f4bf3f9e0d9
RDX: 0000200000000200 RSI: ffffffffffffff9c RDI: 00002000000001c0
RBP: 00007f4bf4035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4bf4226128 R14: 00007f4bf4226090 R15: 00007ffc326e9048
 </TASK>
----------------
Code disassembly (best guess):
   0:	fb                   	sti
   1:	e8 c3 dd ed fc       	call   0xfcedddc9
   6:	48 8d 3d 3c 71 10 0c 	lea    0xc10713c(%rip),%rdi        # 0xc107149
   d:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  12:	e8 b2 dd ed fc       	call   0xfcedddc9
  17:	5b                   	pop    %rbx
  18:	5d                   	pop    %rbp
  19:	e9 f6 ca f3 fb       	jmp    0xfbf3cb14
  1e:	e8 a6 dd ed fc       	call   0xfcedddc9
  23:	48 8d 3d 2f 71 10 0c 	lea    0xc10712f(%rip),%rdi        # 0xc107159
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e8 95 dd ed fc       	call   0xfcedddc9
  34:	5b                   	pop    %rbx
  35:	5d                   	pop    %rbp
  36:	e9 d9 ca f3 fb       	jmp    0xfbf3cb14
  3b:	48 89 df             	mov    %rbx,%rdi
  3e:	e8                   	.byte 0xe8
  3f:	c6                   	.byte 0xc6