bisecting fixing commit since 5b7a52cd2eef952cee8a72512ef370bcdef46636 building syzkaller on be6b1582e9ce6f1ac5d8978e70a6a9f91113f238 testing commit 5b7a52cd2eef952cee8a72512ef370bcdef46636 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 978ff662a3050ed29c439988013c9172afbbcf4cdcec74299f107e6e51480014 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in rhashtable_free_and_destroy testing current HEAD 2760370b164918bd9311e6bf445cf4c118d3463c testing commit 2760370b164918bd9311e6bf445cf4c118d3463c compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: bec03ab2e3ed6dd162b0e33656f3f353fd23a73d8e498cd211d3728f6fdc7238 all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 22m40.144351186s (build: 15m43.226011516s, test: 6m23.248978043s) the crash still happens on HEAD commit msg: Linux 4.14.252 crash: unregister_netdevice: waiting for DEV to become free Bluetooth: hci0 command 0x0409 tx timeout Bluetooth: hci3 command 0x0409 tx timeout Bluetooth: hci2 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: hci1 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci3 command 0x0419 tx timeout