bisecting fixing commit since 1e78030e5e5b2d8b0cad7136caf9cfab986a6bff
building syzkaller on 835dffe7e5d185154a9b147476a17b6301ee139e
testing commit 1e78030e5e5b2d8b0cad7136caf9cfab986a6bff with gcc (GCC) 8.1.0
kernel signature: 032418992b6085a45ead0a53b4652947adceadcb
run #0: crashed: WARNING: refcount bug in hci_register_dev
run #1: crashed: WARNING in kernfs_get
run #2: crashed: general protection fault in kernfs_add_one
run #3: crashed: general protection fault in kernfs_add_one
run #4: crashed: WARNING in hci_unregister_dev
run #5: crashed: WARNING in kernfs_get
run #6: crashed: WARNING in kernfs_get
run #7: crashed: general protection fault in kernfs_add_one
run #8: crashed: WARNING in kernfs_get
run #9: crashed: general protection fault in kernfs_add_one
testing current HEAD bef1d88263ff769f15aa0e1515cdcede84e61d15
testing commit bef1d88263ff769f15aa0e1515cdcede84e61d15 with gcc (GCC) 8.1.0
kernel signature: 1f45df54ff25320b4795bcf0843bdfb2c42dc578
all runs: crashed: BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!
revisions tested: 2, total time: 21m34.604104261s (build: 11m44.119205999s, test: 9m7.26373614s)
the crash still happens on HEAD
commit msg: Merge tag 'pstore-v5.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
crash: BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!
BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!
turning off the locking correctness validator.
CPU: 1 PID: 7886 Comm: kworker/u5:1 Not tainted 5.5.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: hci4 hci_power_on
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x12d/0x187 lib/dump_stack.c:118
 add_chain_cache kernel/locking/lockdep.c:2841 [inline]
 lookup_chain_cache_add kernel/locking/lockdep.c:2915 [inline]
 validate_chain kernel/locking/lockdep.c:2936 [inline]
 __lock_acquire.cold.65+0x18/0x385 kernel/locking/lockdep.c:3955
 lock_acquire+0x194/0x410 kernel/locking/lockdep.c:4485
 process_one_work+0x7c3/0x1630 kernel/workqueue.c:2239
 worker_thread+0x85/0xb60 kernel/workqueue.c:2410
 kthread+0x331/0x3f0 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352