------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 3 PID: 9750 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28 Modules linked in: CPU: 3 UID: 0 PID: 9750 Comm: kbnepd ÒÜ'ç‘ Not tainted 6.14.0-rc2-syzkaller-00041-g4dc1d1bec898 #0 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 a8 18 fc fc 84 db 0f 85 66 ff ff ff e8 fb 1d fc fc c6 05 14 a7 8b 0b 01 90 48 c7 c7 20 8c d2 8b e8 47 f6 bc fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 d8 1d fc fc 0f b6 1d ef a6 8b 0b 31 RSP: 0018:ffffc90003297948 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8179c889 RDX: ffff8880224c0000 RSI: ffffffff8179c896 RDI: 0000000000000001 RBP: ffff88806b83a078 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000003 R12: ffff888069000c00 R13: ffff88806b83a078 R14: ffffffff85e367f0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff88802b700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000032e10ffc CR3: 000000000df80000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 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 lib/klist.c:206 [inline] klist_put+0x11b/0x1b0 lib/klist.c:217 device_del+0x1d9/0x9f0 drivers/base/core.c:3831 unregister_netdevice_many_notify+0x13aa/0x1f30 net/core/dev.c:11838 unregister_netdevice_many net/core/dev.c:11866 [inline] unregister_netdevice_queue+0x307/0x3f0 net/core/dev.c:11736 unregister_netdevice include/linux/netdevice.h:3329 [inline] unregister_netdev+0x21/0x30 net/core/dev.c:11886 bnep_session+0x1fc3/0x2a80 net/bluetooth/bnep/core.c:525 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244