bisecting fixing commit since 7d7d1c0ab3eb7c8d8f63a126535018007823b207 building syzkaller on 8bdd5343e64460868dd1318257a39f1e7fd89471 testing commit 7d7d1c0ab3eb7c8d8f63a126535018007823b207 with gcc (GCC) 8.4.1 20210217 kernel signature: 7d4b544ffb2e69bc533b4b993403cc4ce0a5ec1a4ca10a147c10023b683e0c7f all runs: crashed: INFO: task hung in blkdev_put testing current HEAD 3d3abdc8ebd3c3082e4398fc73ceb4c852b66e85 testing commit 3d3abdc8ebd3c3082e4398fc73ceb4c852b66e85 with gcc (GCC) 8.4.1 20210217 kernel signature: 6f453bbd078c194bce5b95d3c73235cf62a45849439ed518293d62f5c06d67f5 all runs: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 29m14.843614925s (build: 18m53.245398523s, test: 9m58.24894099s) the crash still happens on HEAD commit msg: Linux 4.14.236 crash: unregister_netdevice: waiting for DEV to become free unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 Bluetooth: hci4 command 0x0409 tx timeout Bluetooth: hci1 command 0x0409 tx timeout Bluetooth: hci3 command 0x0409 tx timeout Bluetooth: hci5 command 0x0409 tx timeout Bluetooth: hci2 command 0x0409 tx timeout Bluetooth: hci0 command 0x0409 tx timeout Bluetooth: hci0 command 0x041b tx timeout Bluetooth: hci4 command 0x041b tx timeout Bluetooth: hci2 command 0x041b tx timeout Bluetooth: hci5 command 0x041b tx timeout Bluetooth: hci3 command 0x041b tx timeout Bluetooth: hci1 command 0x041b tx timeout Bluetooth: hci1 command 0x040f tx timeout Bluetooth: hci0 command 0x040f tx timeout Bluetooth: hci3 command 0x040f tx timeout Bluetooth: hci5 command 0x040f tx timeout Bluetooth: hci2 command 0x040f tx timeout Bluetooth: hci4 command 0x040f tx timeout Bluetooth: hci4 command 0x0419 tx timeout Bluetooth: hci1 command 0x0419 tx timeout Bluetooth: hci2 command 0x0419 tx timeout Bluetooth: hci5 command 0x0419 tx timeout Bluetooth: hci3 command 0x0419 tx timeout Bluetooth: hci0 command 0x0419 tx timeout