bisecting fixing commit since 5b7a52cd2eef952cee8a72512ef370bcdef46636 building syzkaller on a7aac492ebbc53e5c7bc4b5bbaf55f428c54093f testing commit 5b7a52cd2eef952cee8a72512ef370bcdef46636 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 9cd05596ea7faf1c125e585ad8ca69c401de9b6e22780a01a104a4c0fb11cfcc run #0: crashed: BUG: unable to handle kernel run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #3: crashed: BUG: unable to handle kernel run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #6: crashed: BUG: unable to handle kernel run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #10: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #11: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #12: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #13: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #14: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #15: crashed: BUG: unable to handle kernel run #16: crashed: BUG: unable to handle kernel run #17: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #18: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #19: crashed: INFO: task hung in usb_get_descriptor testing current HEAD 84bae26850e3b384a45f0f9a5f8b3b5983afacd8 testing commit 84bae26850e3b384a45f0f9a5f8b3b5983afacd8 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 4245682b0b9d4e17fa205ab13a16e3afb33e441dbbebdca1e9fc1c93758e953b all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 34m43.658361564s (build: 24m19.323525363s, test: 9m43.12956405s) the crash still happens on HEAD commit msg: Linux 4.14.284 crash: unregister_netdevice: waiting for DEV to become free Bluetooth: hci4 command 0x0409 tx timeout Bluetooth: hci2 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: hci5 command 0x041b tx timeout Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci3 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout