bisecting fixing commit since 5b7a52cd2eef952cee8a72512ef370bcdef46636 building syzkaller on a7aac492ebbc53e5c7bc4b5bbaf55f428c54093f testing commit 5b7a52cd2eef952cee8a72512ef370bcdef46636 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: cd29040d8051dc8ce829ac1f84560892cec7970961bb0e1e14f51914c00b9603 run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection 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 NULL pointer dereference in vhci_shutdown_connection 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 NULL pointer dereference in vhci_shutdown_connection 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 run #12: crashed: BUG: unable to handle kernel run #13: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #14: crashed: BUG: unable to handle kernel run #15: crashed: BUG: unable to handle kernel run #16: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection 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 hub_port_init testing current HEAD 5f9f3b0057d5c5782985784ba0159b05b4083055 testing commit 5f9f3b0057d5c5782985784ba0159b05b4083055 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 6db4e8a81a5b1ad8b201657e62b78ba4f47d8fa98c3ea2f4ddfd196cc3ce5e23 all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 25m17.824463055s (build: 14m36.631013253s, test: 10m8.085633254s) the crash still happens on HEAD commit msg: Linux 4.14.255 crash: unregister_netdevice: waiting for DEV to become free Bluetooth: hci4 command 0x0409 tx timeout Bluetooth: hci2 command 0x0409 tx timeout Bluetooth: hci3 command 0x0409 tx timeout Bluetooth: hci0 command 0x0409 tx timeout Bluetooth: hci1 command 0x0409 tx timeout unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci5 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci3 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout Bluetooth: hci1 command 0x0419 tx timeout