bisecting fixing commit since 728254541ebcc7fee869c3c4c3f36f96be791edb
building syzkaller on 7509bf360eba1461ac6059e4cacfbc29c9d2d4c7
testing commit 728254541ebcc7fee869c3c4c3f36f96be791edb with gcc (GCC) 8.1.0
kernel signature: f189dc1c2f2d6d67f4976f93f5c13155e0b58298855e54557760ca1080aebad6
run #0: crashed: WARNING in kernfs_put
run #1: crashed: general protection fault in kernfs_add_one
run #2: crashed: general protection fault in kernfs_add_one
run #3: crashed: WARNING in kernfs_get
run #4: crashed: WARNING in kernfs_get
run #5: crashed: WARNING in kernfs_get
run #6: crashed: WARNING in kernfs_get
run #7: crashed: WARNING: refcount bug in hci_register_dev
run #8: crashed: WARNING in kernfs_get
run #9: crashed: WARNING in kernfs_get
testing current HEAD fb33c6510d5595144d585aa194d377cf74d31911
testing commit fb33c6510d5595144d585aa194d377cf74d31911 with gcc (GCC) 8.1.0
kernel signature: 95e84471dfd2858ebd2380f1e12ecfa841c96d4232080fe361cf0ebd045ad66d
all runs: crashed: BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!
revisions tested: 2, total time: 21m48.061135656s (build: 11m55.565051369s, test: 9m4.031586453s)
the crash still happens on HEAD
commit msg: Linux 5.6-rc6
crash: BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!
BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!
turning off the locking correctness validator.
CPU: 0 PID: 8884 Comm: kworker/u5:2 Not tainted 5.6.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: hci2 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:2840 [inline]
 lookup_chain_cache_add kernel/locking/lockdep.c:2914 [inline]
 validate_chain kernel/locking/lockdep.c:2935 [inline]
 __lock_acquire.cold.65+0x18/0x385 kernel/locking/lockdep.c:3954
 lock_acquire+0x194/0x410 kernel/locking/lockdep.c:4484
 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
 _raw_spin_lock_irq+0x61/0x80 kernel/locking/spinlock.c:167
 spin_lock_irq include/linux/spinlock.h:363 [inline]
 flush_workqueue_prep_pwqs+0x143/0x420 kernel/workqueue.c:2732
 flush_workqueue+0x44b/0x13d0 kernel/workqueue.c:2803
 drain_workqueue+0x148/0x340 kernel/workqueue.c:2942
 hci_dev_do_close+0x1d8/0xe30 net/bluetooth/hci_core.c:1714
 hci_power_on+0x163/0x4d0 net/bluetooth/hci_core.c:2211
 process_one_work+0x88b/0x1680 kernel/workqueue.c:2266
 worker_thread+0x85/0xb60 kernel/workqueue.c:2412
 kthread+0x331/0x3f0 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352