bisecting fixing commit since 5b7a52cd2eef952cee8a72512ef370bcdef46636 building syzkaller on be6b1582e9ce6f1ac5d8978e70a6a9f91113f238 testing commit 5b7a52cd2eef952cee8a72512ef370bcdef46636 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: ecfbbbeb6004b77fa5747f0b8008206fdd506405edf6854a57769f7d5243041e all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in rhashtable_free_and_destroy testing current HEAD 74766a973637a02c32c04c1c6496e114e4855239 testing commit 74766a973637a02c32c04c1c6496e114e4855239 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 3ea391cdbfb85c461ee6290b7af1e7a18aa0069c5161fa7c8d85dee28f7729f2 all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 21m3.911233099s (build: 14m37.010766473s, test: 5m57.810258671s) the crash still happens on HEAD commit msg: Linux 4.14.275 crash: unregister_netdevice: waiting for DEV to become free Bluetooth: hci2 command 0x0409 tx timeout Bluetooth: hci3 command 0x0409 tx timeout Bluetooth: hci4 command 0x0409 tx timeout Bluetooth: hci5 command 0x0409 tx timeout Bluetooth: hci1 command 0x0409 tx timeout unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci3 command 0x0419 tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout