bisecting fixing commit since 7d7d1c0ab3eb7c8d8f63a126535018007823b207 building syzkaller on f54a5c0916af7d798b204eb70c484f154d69e0a3 testing commit 7d7d1c0ab3eb7c8d8f63a126535018007823b207 with gcc (GCC) 8.4.1 20210217 kernel signature: 75ad5433697df323807fb5e71d625634a11066139f69ad5d346953905c50dced all runs: crashed: WARNING: suspicious RCU usage in tcp_disconnect testing current HEAD cfb41ef9deb1e6572ac218ddfcec9567e5d1c101 testing commit cfb41ef9deb1e6572ac218ddfcec9567e5d1c101 with gcc (GCC) 8.4.1 20210217 kernel signature: 31a21eb8cf054f865f55f304a60890ab307f574927190afd2d11e332c2843459 all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 28m31.436526305s (build: 21m36.83880046s, test: 6m24.988716337s) the crash still happens on HEAD commit msg: Linux 4.14.237 crash: unregister_netdevice: waiting for DEV to become free unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 Bluetooth: hci0 command 0x0409 tx timeout Bluetooth: hci2 command 0x0409 tx timeout Bluetooth: hci1 command 0x0409 tx timeout Bluetooth: hci3 command 0x0409 tx timeout Bluetooth: hci5 command 0x0409 tx timeout Bluetooth: hci4 command 0x0409 tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci5 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci3 command 0x0419 tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout