------------[ 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#3: syz.3.195/6501
Modules linked in:
CPU: 3 UID: 0 PID: 6501 Comm: syz.3.195 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:refcount_warn_saturate+0x111/0x130 lib/refcount.c:25
Code: 06 e8 23 58 ee fc 48 8d 3d 4c 83 12 0c 67 48 0f b9 3a e8 12 58 ee fc 5b 5d c3 cc cc cc cc e8 06 58 ee fc 48 8d 3d 3f 83 12 0c <67> 48 0f b9 3a e8 f5 57 ee fc 5b 5d e9 4e 8a a0 06 48 89 df e8 e6
RSP: 0018:ffffc90030e07c78 EFLAGS: 00010283
RAX: 0000000000000f4c RBX: ffff88802806eb1c RCX: ffffc90007b92000
RDX: 0000000000080000 RSI: ffffffff851b58fa RDI: ffffffff912ddc40
RBP: 0000000000000002 R08: 0000000000000005 R09: 0000000000000004
R10: 0000000000000002 R11: 0000000000000000 R12: ffff88802806eb1c
R13: ffff888012f4dfd8 R14: ffffc90030e07d28 R15: ffff88806d87c000
FS:  0000000000000000(0000) GS:ffff888096edf000(0063) knlGS:00000000f53fdb40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000006062f000 CR4: 0000000000352ef0
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]
 __ia32_sys_symlinkat+0x9b/0xe0 fs/namei.c:5700
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xe7/0x970 arch/x86/entry/syscall_32.c:307
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf700efec
Code: Unable to access opcode bytes at 0xf700efc2.
RSP: 002b:00000000f53fd50c EFLAGS: 00000292 ORIG_RAX: 0000000000000130
RAX: ffffffffffffffda RBX: 00000000800001c0 RCX: 00000000ffffff9c
RDX: 0000000080000200 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	e8 23 58 ee fc       	call   0xfcee5828
   5:	48 8d 3d 4c 83 12 0c 	lea    0xc12834c(%rip),%rdi        # 0xc128358
   c:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  11:	e8 12 58 ee fc       	call   0xfcee5828
  16:	5b                   	pop    %rbx
  17:	5d                   	pop    %rbp
  18:	c3                   	ret
  19:	cc                   	int3
  1a:	cc                   	int3
  1b:	cc                   	int3
  1c:	cc                   	int3
  1d:	e8 06 58 ee fc       	call   0xfcee5828
  22:	48 8d 3d 3f 83 12 0c 	lea    0xc12833f(%rip),%rdi        # 0xc128368
* 29:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2e:	e8 f5 57 ee fc       	call   0xfcee5828
  33:	5b                   	pop    %rbx
  34:	5d                   	pop    %rbp
  35:	e9 4e 8a a0 06       	jmp    0x6a08a88
  3a:	48 89 df             	mov    %rbx,%rdi
  3d:	e8                   	.byte 0xe8
  3e:	e6                   	.byte 0xe6