------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 7883 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Modules linked in:
CPU: 1 UID: 0 PID: 7883 Comm: kbnepd bnep0 Not tainted 6.15.0-rc6-syzkaller-00208-g3c21441eeffc #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Code: ff 89 de e8 18 31 ea fc 84 db 0f 85 66 ff ff ff e8 2b 36 ea fc c6 05 68 5f 9c 0b 01 90 48 c7 c7 a0 36 f4 8b e8 87 c3 a9 fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 08 36 ea fc 0f b6 1d 43 5f 9c 0b 31
RSP: 0018:ffffc90003fff948 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff817ad548
RDX: ffff88802b2c8000 RSI: ffffffff817ad555 RDI: 0000000000000001
RBP: ffff88804d035c78 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880348da400
R13: ffff88804d035c78 R14: ffffffff85fd9be0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880d6adf000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000040 CR3: 0000000030881000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __refcount_sub_and_test include/linux/refcount.h:400 [inline]
 __refcount_dec_and_test include/linux/refcount.h:432 [inline]
 refcount_dec_and_test include/linux/refcount.h:450 [inline]
 kref_put include/linux/kref.h:64 [inline]
 klist_dec_and_del lib/klist.c:206 [inline]
 klist_put+0x11b/0x1b0 lib/klist.c:217
 device_del+0x1d8/0x9f0 drivers/base/core.c:3858
 unregister_netdevice_many_notify+0x1904/0x26f0 net/core/dev.c:12008
 unregister_netdevice_many net/core/dev.c:12036 [inline]
 unregister_netdevice_queue+0x305/0x3f0 net/core/dev.c:11879
 unregister_netdevice include/linux/netdevice.h:3374 [inline]
 unregister_netdev+0x1f/0x60 net/core/dev.c:12054
 bnep_session+0x224e/0x2d80 net/bluetooth/bnep/core.c:525
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>