bisecting fixing commit since 7d7d1c0ab3eb7c8d8f63a126535018007823b207 building syzkaller on f54a5c0916af7d798b204eb70c484f154d69e0a3 testing commit 7d7d1c0ab3eb7c8d8f63a126535018007823b207 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 9ff1016c88bfdbdb60db5d7adc9db10914df6fe073ebc1bb4d20dd53d49e01ec all runs: crashed: WARNING: suspicious RCU usage in tcp_disconnect testing current HEAD 5f9f3b0057d5c5782985784ba0159b05b4083055 testing commit 5f9f3b0057d5c5782985784ba0159b05b4083055 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 1cadcb91d769abcc5e657f0ba826085214e1408752d67e5d4060bfdf73bfd581 all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 26m59.205335687s (build: 19m50.63121946s, test: 6m19.471898593s) the crash still happens on HEAD commit msg: Linux 4.14.255 crash: unregister_netdevice: waiting for DEV to become free Bluetooth: hci0 command 0x0409 tx timeout Bluetooth: hci4 command 0x0409 tx timeout Bluetooth: hci1 command 0x0409 tx timeout Bluetooth: hci5 command 0x0409 tx timeout Bluetooth: hci3 command 0x0409 tx timeout unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci3 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout