bisecting fixing commit since 7d7d1c0ab3eb7c8d8f63a126535018007823b207 building syzkaller on a343ba6b077a3efe7feb57783dcbb7496d2c3572 testing commit 7d7d1c0ab3eb7c8d8f63a126535018007823b207 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 7e1724549f0168d4b223d5dcacf53fb954c02cead0112ee7d1e3d1b0a4a87698 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: no output from test machine run #15: crashed: no output from test machine 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 5f9f3b0057d5c5782985784ba0159b05b4083055 testing commit 5f9f3b0057d5c5782985784ba0159b05b4083055 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: d30e1b7992824c85aec3cd857ffa2f2b6f907147f4f99b027265e971e3e8f6cf all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 26m46.80287701s (build: 15m15.85524784s, test: 11m5.321858402s) the crash still happens on HEAD commit msg: Linux 4.14.255 crash: unregister_netdevice: waiting for DEV to become free Bluetooth: hci3 command 0x0409 tx timeout Bluetooth: hci4 command 0x0409 tx timeout Bluetooth: hci0 command 0x0409 tx timeout Bluetooth: hci2 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: hci2 command 0x041b tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout Bluetooth: hci3 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout