bisecting fixing commit since 2c8a3fceddf0dd87f278e7a5e01350f86f844b1c building syzkaller on 14052202e8d8d0bb407512b6861e9085f9171241 testing commit 2c8a3fceddf0dd87f278e7a5e01350f86f844b1c compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: a7ea22f17e1f2c3bc9ab55d39d57ecf8a806f113f98737d84f8b35c737b9bd62 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 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: INFO: task hung in usb_get_descriptor run #14: crashed: INFO: task hung in usb_get_descriptor run #15: crashed: INFO: task hung in usb_get_descriptor run #16: crashed: INFO: task hung in usb_get_descriptor run #17: OK run #18: OK run #19: OK testing current HEAD f96eb53cbd76415edfba99c2cfa88567a885a428 testing commit f96eb53cbd76415edfba99c2cfa88567a885a428 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: c25b007aa13e8c0e616ac3b7045390813aa6e5e18d734265ff72b11ca77b9366 all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 29m48.765287394s (build: 14m44.415229004s, test: 14m31.000874914s) the crash still happens on HEAD commit msg: Linux 4.14.246 crash: unregister_netdevice: waiting for DEV to become free Bluetooth: hci1 command 0x0409 tx timeout Bluetooth: hci0 command 0x0409 tx timeout unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 Bluetooth: hci2 command 0x0409 tx timeout Bluetooth: hci5 command 0x0409 tx timeout Bluetooth: hci4 command 0x0409 tx timeout Bluetooth: hci3 command 0x0409 tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci3 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout