------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 9869 at lib/refcount.c:28 refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28 Modules linked in: CPU: 1 UID: 0 PID: 9869 Comm: kbnepd bnep0 Not tainted 6.13.0-syzkaller-09701-g0e6dc66b5c5f #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 RIP: 0010:refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28 Code: 20 3b 60 8c e8 17 aa 97 fc 90 0f 0b 90 90 eb 99 e8 eb f0 d6 fc c6 05 80 e4 1c 0b 01 90 48 c7 c7 80 3b 60 8c e8 f7 a9 97 fc 90 <0f> 0b 90 90 e9 76 ff ff ff e8 c8 f0 d6 fc c6 05 5a e4 1c 0b 01 90 RSP: 0018:ffffc90004457720 EFLAGS: 00010246 RAX: 4009a0e317f62900 RBX: ffff888028bc5c78 RCX: ffff88807e813c00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000003 R08: ffffffff81802842 R09: fffffbfff1cfa57c R10: dffffc0000000000 R11: fffffbfff1cfa57c R12: ffff888028bc5c60 R13: 1ffff11005178b8c R14: ffff888028bc5c60 R15: ffffffff862a9000 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff125d5e80 CR3: 000000002847c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_sub_and_test include/linux/refcount.h:275 [inline] __refcount_dec_and_test include/linux/refcount.h:307 [inline] refcount_dec_and_test include/linux/refcount.h:325 [inline] kref_put include/linux/kref.h:64 [inline] klist_dec_and_del+0x3ec/0x3f0 lib/klist.c:206 klist_put lib/klist.c:217 [inline] klist_del+0xa7/0x110 lib/klist.c:230 device_del+0x2c9/0x9b0 drivers/base/core.c:3831 unregister_netdevice_many_notify+0x19b4/0x1f10 net/core/dev.c:11824 unregister_netdevice_many net/core/dev.c:11852 [inline] unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11722 unregister_netdevice include/linux/netdevice.h:3329 [inline] unregister_netdev+0x21/0x30 net/core/dev.c:11872 bnep_session+0x2e3c/0x3030 net/bluetooth/bnep/core.c:525 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244