bisecting fixing commit since 5b7a52cd2eef952cee8a72512ef370bcdef46636 building syzkaller on a7aac492ebbc53e5c7bc4b5bbaf55f428c54093f testing commit 5b7a52cd2eef952cee8a72512ef370bcdef46636 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 9b670d8879bcb17e278a7dfbad25c9e1681314eb7e598c925bdff01fb82f0125 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 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 NULL pointer dereference in vhci_shutdown_connection 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: INFO: task hung in hub_port_init run #15: crashed: INFO: task hung in hub_port_init run #16: crashed: INFO: task hung in hub_port_init run #17: crashed: INFO: task hung in hub_port_init run #18: crashed: INFO: task hung in usb_get_descriptor run #19: crashed: INFO: task hung in hub_port_init testing current HEAD 964f3712e6a7447d9d3203f2be3f6c50e78ea179 testing commit 964f3712e6a7447d9d3203f2be3f6c50e78ea179 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 1cd30c69451b3726d8edcfa1f395fec18e6f2e2d2ccd0a036400a5b3b605c62d all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 28m50.981033972s (build: 18m14.445882425s, test: 10m8.963605779s) the crash still happens on HEAD commit msg: Linux 4.14.240 crash: unregister_netdevice: waiting for DEV to become free Bluetooth: hci5 command 0x0409 tx timeout Bluetooth: hci0 command 0x0409 tx timeout Bluetooth: hci4 command 0x0409 tx timeout Bluetooth: hci1 command 0x0409 tx timeout Bluetooth: hci3 command 0x0409 tx timeout unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci3 command 0x0419 tx timeout