bisecting fixing commit since 6b6446efedb27c2766745a04f9b5d4449f51391d building syzkaller on cba33199be220cbf61f7c0c8223d88a25a913d6f testing commit 6b6446efedb27c2766745a04f9b5d4449f51391d compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: c83a3e5dad5e1d7ab5afa03a4de212658028083f4f1b6817557e2b0581c26787 all runs: crashed: INFO: task hung in rtnl_lock testing current HEAD f6b016a9d961296d2db609d0259654371625e22e testing commit f6b016a9d961296d2db609d0259654371625e22e compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 714afc131aee8529fe7bd55ce2021def0e20ea17945b239f2689ebd7cf343922 all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 35m31.467420832s (build: 24m37.382677531s, test: 10m22.965773423s) the crash still happens on HEAD commit msg: Linux 4.14.251 crash: unregister_netdevice: waiting for DEV to become free Bluetooth: hci0 command 0x0409 tx timeout syz-executor.0 (7276) used greatest stack depth: 24184 bytes left can: request_module (can-proto-0) failed. can: request_module (can-proto-0) failed. can: request_module (can-proto-0) failed. unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 Bluetooth: hci4 command 0x0409 tx timeout Bluetooth: hci2 command 0x0409 tx timeout Bluetooth: hci5 command 0x0409 tx timeout Bluetooth: hci0 command 0x0409 tx timeout Bluetooth: hci3 command 0x0409 tx timeout Bluetooth: hci1 command 0x0409 tx timeout Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci3 command 0x0419 tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout