------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 13292 at lib/refcount.c:28 refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28 Modules linked in: CPU: 0 UID: 0 PID: 13292 Comm: kbnepd bnep0 Not tainted 6.16.0-rc2-syzkaller-00179-g9caca6ac0e26 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28 Code: 00 41 e2 8b e8 f7 92 c2 fc 90 0f 0b 90 90 eb d7 e8 3b e8 fe fc c6 05 e7 96 c9 0a 01 90 48 c7 c7 60 41 e2 8b e8 d7 92 c2 fc 90 <0f> 0b 90 90 eb b7 e8 1b e8 fe fc c6 05 c4 96 c9 0a 01 90 48 c7 c7 RSP: 0018:ffffc90004ebf6a0 EFLAGS: 00010246 RAX: 3047bc996cf46100 RBX: 0000000000000003 RCX: ffff88804e21da00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002 RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffffbfff1bfa9ec R12: dffffc0000000000 R13: ffff88804eb8d860 R14: ffff88804eb8d878 R15: ffffffff85f65610 FS: 0000000000000000(0000) GS:ffff888125c51000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd7eac6e20 CR3: 000000000df38000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __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:3858 unregister_netdevice_many_notify+0x1d52/0x2320 net/core/dev.c:12112 unregister_netdevice_many net/core/dev.c:12140 [inline] unregister_netdevice_queue+0x33c/0x380 net/core/dev.c:11984 unregister_netdevice include/linux/netdevice.h:3379 [inline] unregister_netdev+0x1f/0x60 net/core/dev.c:12158 bnep_session+0x294d/0x2b40 net/bluetooth/bnep/core.c:525 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245