bisecting fixing commit since 2c8a3fceddf0dd87f278e7a5e01350f86f844b1c building syzkaller on fc9fd31ee7998c8b747752791000ea4eef07b5c6 testing commit 2c8a3fceddf0dd87f278e7a5e01350f86f844b1c compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 3ff0ca2c1a84410c59ed040c5bef2d1c363f3aeccdc7e20be145ff7ce4e90ea8 all runs: crashed: BUG: looking up invalid subclass: NUM testing current HEAD eb045674aab31aa55a4f9aec27cce36e3d946a21 testing commit eb045674aab31aa55a4f9aec27cce36e3d946a21 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: c7f778fb911681905b3cf98f3f72c64adacbac28ce5f3ab4bd3869399b2cc301 all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 22m34.537444554s (build: 15m52.411218079s, test: 6m19.149217809s) the crash still happens on HEAD commit msg: Linux 4.14.272 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: hci0 command 0x0409 tx timeout Bluetooth: hci1 command 0x0409 tx timeout unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout Bluetooth: hci3 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout