bisecting fixing commit since 7d7d1c0ab3eb7c8d8f63a126535018007823b207
building syzkaller on f54a5c0916af7d798b204eb70c484f154d69e0a3
testing commit 7d7d1c0ab3eb7c8d8f63a126535018007823b207 with gcc (GCC) 8.4.1 20210217
kernel signature: 9731b0de24da8cd29ec27b0c550b88a2b024d8dd3fde4c63b135b485f971fa4d
run #0: crashed: KASAN: use-after-free Read in nbd_put
run #1: crashed: WARNING: refcount bug in nbd_put
run #2: crashed: KASAN: use-after-free Read in nbd_put
run #3: crashed: KASAN: use-after-free Read in nbd_put
run #4: crashed: WARNING: refcount bug in nbd_put
run #5: crashed: KASAN: use-after-free Write in ex_handler_refcount
run #6: crashed: KASAN: use-after-free Read in nbd_put
run #7: crashed: KASAN: use-after-free Read in nbd_put
run #8: crashed: KASAN: use-after-free Read in nbd_put
run #9: crashed: KASAN: use-after-free Read in nbd_put
run #10: crashed: KASAN: use-after-free Read in nbd_put
run #11: crashed: KASAN: use-after-free Read in nbd_put
run #12: crashed: KASAN: use-after-free Read in nbd_put
run #13: crashed: KASAN: use-after-free Read in nbd_put
run #14: crashed: WARNING: refcount bug in nbd_put
run #15: crashed: KASAN: use-after-free Read in nbd_put
run #16: crashed: KASAN: use-after-free Read in nbd_put
run #17: crashed: WARNING: refcount bug in nbd_put
run #18: crashed: KASAN: use-after-free Read in nbd_put
run #19: crashed: WARNING: refcount bug in nbd_put
testing current HEAD 3d3abdc8ebd3c3082e4398fc73ceb4c852b66e85
testing commit 3d3abdc8ebd3c3082e4398fc73ceb4c852b66e85 with gcc (GCC) 8.4.1 20210217
kernel signature: 2a1a96455eb59d515bea379bd3cf01dcb30bd7d1ed2aaeb406931f385567af91
all runs: crashed: unregister_netdevice: waiting for DEV to become free
revisions tested: 2, total time: 21m6.08127116s (build: 14m30.093432831s, test: 6m16.673983113s)
the crash still happens on HEAD
commit msg: Linux 4.14.236
crash: unregister_netdevice: waiting for DEV to become free
Bluetooth: hci0 command 0x0409 tx timeout
Bluetooth: hci5 command 0x0409 tx timeout
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: hci2 command 0x0409 tx timeout
Bluetooth: hci0 command 0x041b tx timeout
Bluetooth: hci2 command 0x041b tx timeout
Bluetooth: hci4 command 0x041b tx timeout
Bluetooth: hci3 command 0x041b tx timeout
Bluetooth: hci5 command 0x041b tx timeout
Bluetooth: hci1 command 0x041b 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: hci2 command 0x040f 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
Bluetooth: hci1 command 0x0419 tx timeout
Bluetooth: hci3 command 0x0419 tx timeout