bisecting fixing commit since 7d7d1c0ab3eb7c8d8f63a126535018007823b207 building syzkaller on a343ba6b077a3efe7feb57783dcbb7496d2c3572 testing commit 7d7d1c0ab3eb7c8d8f63a126535018007823b207 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: ccc4968bc5f9f191f67a4edcb1874ff469b18a74f17e861e1025a6609355ec4e run #0: crashed: INFO: task hung in grab_super run #1: crashed: INFO: task hung in grab_super run #2: crashed: INFO: task hung in grab_super run #3: crashed: INFO: task hung in grab_super run #4: crashed: INFO: task hung in grab_super run #5: crashed: INFO: task hung in grab_super run #6: crashed: INFO: task hung in grab_super run #7: crashed: INFO: task hung in grab_super run #8: crashed: INFO: task hung in grab_super run #9: crashed: INFO: task hung in grab_super run #10: crashed: INFO: task hung in grab_super run #11: crashed: INFO: task hung in grab_super run #12: crashed: INFO: task hung in grab_super run #13: crashed: INFO: task hung in grab_super run #14: crashed: INFO: task hung in grab_super run #15: crashed: INFO: task hung in grab_super run #16: crashed: no output from test machine run #17: crashed: no output from test machine run #18: crashed: no output from test machine run #19: crashed: no output from test machine testing current HEAD ed99bf0e81b558df39f7db2fa96d0228be4198c6 testing commit ed99bf0e81b558df39f7db2fa96d0228be4198c6 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 4972a7a64f6072e969e3054473dff8c00597671182b52eb7637cbf7693cdc52d all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 29m23.399334255s (build: 17m33.514889634s, test: 11m8.212427995s) the crash still happens on HEAD commit msg: Linux 4.14.250 crash: unregister_netdevice: waiting for DEV to become free Bluetooth: hci2 command 0x0409 tx timeout Bluetooth: hci0 command 0x0409 tx timeout Bluetooth: hci3 command 0x0409 tx timeout Bluetooth: hci4 command 0x0409 tx timeout Bluetooth: hci5 command 0x0409 tx timeout unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci3 command 0x0419 tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout