bisecting fixing commit since 2c8a3fceddf0dd87f278e7a5e01350f86f844b1c building syzkaller on fc9fd31ee7998c8b747752791000ea4eef07b5c6 testing commit 2c8a3fceddf0dd87f278e7a5e01350f86f844b1c compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: e07f1e69d1799c499f4782f65ffb266b65f71fcdf9a6cef76a9839eef0b0cdc5 all runs: crashed: BUG: looking up invalid subclass: NUM testing current HEAD 66722c42ec916e92cadda46316f8f6e3fdcaedc6 testing commit 66722c42ec916e92cadda46316f8f6e3fdcaedc6 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: ab8aabd7a6427da321e251a45d94e8460c78ab57440fe19c1e9d56e5304685c4 all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 28m6.550509102s (build: 21m5.435000815s, test: 6m24.541867513s) the crash still happens on HEAD commit msg: Linux 4.14.256 crash: unregister_netdevice: waiting for DEV to become free Bluetooth: hci2 command 0x0409 tx timeout Bluetooth: hci5 command 0x0409 tx timeout Bluetooth: hci1 command 0x0409 tx timeout Bluetooth: hci3 command 0x0409 tx timeout Bluetooth: hci0 command 0x0409 tx timeout unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci3 command 0x0419 tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout