bisecting fixing commit since e0f8b8a65a473a8baa439cf865a694bbeb83fe90
building syzkaller on 5d7b90f1af2e3bf33992b75e7fcf0bab6bf49bd6
testing commit e0f8b8a65a473a8baa439cf865a694bbeb83fe90 with gcc (GCC) 8.4.1 20210217
kernel signature: 31b63e046764bc64943f7e0c7fe00d3bf8abcbb6a8f2f2b195573fddd7706306
run #0: crashed: possible deadlock in pty_write
run #1: crashed: possible deadlock in console_unlock
run #2: crashed: possible deadlock in console_unlock
run #3: crashed: possible deadlock in console_unlock
run #4: crashed: possible deadlock in pty_write
run #5: crashed: possible deadlock in console_unlock
run #6: crashed: possible deadlock in console_unlock
run #7: crashed: possible deadlock in console_unlock
run #8: crashed: possible deadlock in pty_write
run #9: crashed: possible deadlock in console_unlock
run #10: crashed: possible deadlock in console_unlock
run #11: crashed: possible deadlock in console_unlock
run #12: crashed: possible deadlock in console_unlock
run #13: crashed: possible deadlock in pty_write
run #14: crashed: possible deadlock in console_unlock
run #15: crashed: possible deadlock in pty_write
run #16: crashed: possible deadlock in console_unlock
run #17: crashed: possible deadlock in console_unlock
run #18: crashed: possible deadlock in pty_write
run #19: crashed: possible deadlock in pty_write
testing current HEAD 4e68c9b0763ff55eaa69d6e519f07515f1c9037b
testing commit 4e68c9b0763ff55eaa69d6e519f07515f1c9037b with gcc (GCC) 8.4.1 20210217
kernel signature: 9d11b771baa82cb7dd19eaf800b302c1c5f100226bfa552f49534c1f91ab82f5
all runs: crashed: unregister_netdevice: waiting for DEV to become free
revisions tested: 2, total time: 24m2.666776236s (build: 17m4.544043261s, test: 6m30.245773835s)
the crash still happens on HEAD
commit msg: Linux 4.14.239
crash: unregister_netdevice: waiting for DEV to become free
unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1