------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28, CPU#0: kbnepd bnep0/16115
Modules linked in:
CPU: 0 UID: 0 PID: 16115 Comm: kbnepd bnep0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28
Code: 60 2b 03 8c e8 97 e4 b5 fc 90 0f 0b 90 90 eb d7 e8 6b 74 f2 fc c6 05 51 61 df 0a 01 90 48 c7 c7 c0 2b 03 8c e8 77 e4 b5 fc 90 <0f> 0b 90 90 eb b7 e8 4b 74 f2 fc c6 05 2e 61 df 0a 01 90 48 c7 c7
RSP: 0018:ffffc9000b8a76e0 EFLAGS: 00010246
RAX: 9d36f8dfbb19e600 RBX: 0000000000000003 RCX: ffff888026141e40
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1c3a65c R12: dffffc0000000000
R13: ffff888032228060 R14: ffff888032228078 R15: ffffffff860839f0
FS:  0000000000000000(0000) GS:ffff8881259fc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32321ff8 CR3: 000000005e178000 CR4: 00000000003526f0
DR0: 0000000000000008 DR1: 0000000000000002 DR2: 0000000000000081
DR3: ffffffffefffff14 DR6: 00000000ffff0ff0 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+0x3c7/0x3d0 lib/klist.c:206
 klist_put lib/klist.c:217 [inline]
 klist_del+0xa6/0x110 lib/klist.c:230
 device_del+0x280/0x8e0 drivers/base/core.c:3855
 unregister_netdevice_many_notify+0x1a6b/0x1ff0 net/core/dev.c:12302
 unregister_netdevice_many net/core/dev.c:12330 [inline]
 unregister_netdevice_queue+0x33c/0x380 net/core/dev.c:12174
 unregister_netdevice include/linux/netdevice.h:3392 [inline]
 unregister_netdev+0x1f/0x60 net/core/dev.c:12348
 bnep_session+0x294d/0x2b40 net/bluetooth/bnep/core.c:525
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>