bisecting fixing commit since 7d7d1c0ab3eb7c8d8f63a126535018007823b207 building syzkaller on ed7d41c582d6f194ff35353d8bfdf7681dc0718e testing commit 7d7d1c0ab3eb7c8d8f63a126535018007823b207 with gcc (GCC) 8.4.1 20210217 kernel signature: 8a4c768d40fcfc05eb6eaf9d113db80c94786f426f7539315c5c3fba8586e0f5 run #0: crashed: INFO: task hung in blkdev_reread_part run #1: crashed: INFO: task hung in lo_open run #2: crashed: INFO: task hung in loop_control_ioctl run #3: crashed: INFO: task hung in blkdev_reread_part run #4: crashed: INFO: task hung in lo_open run #5: crashed: INFO: task hung in lo_open run #6: crashed: INFO: task hung in lo_open run #7: crashed: INFO: task hung in lo_open run #8: crashed: INFO: task hung in lo_open run #9: crashed: INFO: task hung in lo_open run #10: crashed: INFO: task hung in lo_open run #11: crashed: INFO: task hung in lo_open run #12: crashed: INFO: task hung in lo_open run #13: crashed: INFO: task hung in loop_control_ioctl run #14: crashed: INFO: task hung in lo_open run #15: crashed: INFO: task hung in lo_release run #16: crashed: INFO: task hung in lo_release run #17: crashed: INFO: task hung in lo_open run #18: crashed: INFO: task hung in lo_open run #19: crashed: INFO: task hung in lo_open testing current HEAD 4e68c9b0763ff55eaa69d6e519f07515f1c9037b testing commit 4e68c9b0763ff55eaa69d6e519f07515f1c9037b with gcc (GCC) 8.4.1 20210217 kernel signature: df79ab14bf65a5f700a8b89e88594468ae85b584d2b964516f13a031f99e684a all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 24m46.444724404s (build: 14m32.42134526s, test: 9m52.01850375s) the crash still happens on HEAD commit msg: Linux 4.14.239 crash: unregister_netdevice: waiting for DEV to become free 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: hci3 command 0x0409 tx timeout Bluetooth: hci5 command 0x0409 tx timeout Bluetooth: hci0 command 0x0409 tx timeout Bluetooth: hci1 command 0x0409 tx timeout Bluetooth: hci2 command 0x0409 tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci4 command 0x0419 tx timeout Bluetooth: hci0 command 0x0419 tx timeout Bluetooth: hci3 command 0x0419 tx timeout