bisecting fixing commit since 5b7a52cd2eef952cee8a72512ef370bcdef46636 building syzkaller on a7aac492ebbc53e5c7bc4b5bbaf55f428c54093f testing commit 5b7a52cd2eef952cee8a72512ef370bcdef46636 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 4d571ce8648b8a262343a40b64d4012031c737201bb51e117119ee5bf56234cd run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #1: crashed: BUG: unable to handle kernel run #2: crashed: BUG: unable to handle kernel 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 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 run #14: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection run #15: crashed: BUG: unable to handle kernel NULL pointer dereference in vhci_shutdown_connection 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: INFO: task hung in usb_get_descriptor run #19: crashed: INFO: task hung in usb_get_descriptor testing current HEAD 162b95d01320370b80cb2d5724cea4ae538ac740 testing commit 162b95d01320370b80cb2d5724cea4ae538ac740 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 38dbbe0667d2a80edf1b6fdb437238ab2ad949a5a4b438cb8632e58cd3e2a46c all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 27m43.86834826s (build: 17m27.469504603s, test: 9m41.436034628s) the crash still happens on HEAD commit msg: Linux 4.14.244 crash: unregister_netdevice: waiting for DEV to become free Bluetooth: hci2 command 0x0409 tx timeout Bluetooth: hci1 command 0x0409 tx timeout Bluetooth: hci3 command 0x0409 tx timeout Bluetooth: hci5 command 0x0409 tx timeout Bluetooth: hci4 command 0x0409 tx timeout unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci3 command 0x0419 tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout