bisecting fixing commit since 14b58326976de6ef3998eefec1dd7f8b38b97a75
building syzkaller on ff51e5229e0ee846d2fd687cb0dbca13de758c66
testing commit 14b58326976de6ef3998eefec1dd7f8b38b97a75 with gcc (GCC) 8.1.0
kernel signature: ab703807d4636ae7659eb84e1105c114af94073c94d996dece2451d1953eb0e9
run #0: crashed: WARNING: ODEBUG bug in bt_link_release
run #1: crashed: WARNING: ODEBUG bug in bt_link_release
run #2: crashed: WARNING: ODEBUG bug in bt_link_release
run #3: crashed: KASAN: use-after-free Read in sco_chan_del
run #4: crashed: KASAN: use-after-free Read in sco_chan_del
run #5: crashed: WARNING: ODEBUG bug in bt_link_release
run #6: crashed: WARNING: ODEBUG bug in bt_link_release
run #7: crashed: KASAN: use-after-free Read in sco_chan_del
run #8: crashed: WARNING: ODEBUG bug in bt_link_release
run #9: crashed: WARNING: ODEBUG bug in bt_link_release
testing current HEAD c196b3a9c83ae3491280b739d231d02b3cb9d041
testing commit c196b3a9c83ae3491280b739d231d02b3cb9d041 with gcc (GCC) 8.1.0
kernel signature: 49d4e46013466911d1e31e3335a34948d5526e675e09ccfdc182aa10b9f7cdf0
run #0: crashed: KASAN: use-after-free Read in sco_chan_del
run #1: crashed: WARNING: ODEBUG bug in bt_link_release
run #2: crashed: WARNING: ODEBUG bug in bt_link_release
run #3: crashed: WARNING: ODEBUG bug in bt_link_release
run #4: crashed: WARNING: ODEBUG bug in bt_link_release
run #5: crashed: WARNING: ODEBUG bug in bt_link_release
run #6: crashed: WARNING: ODEBUG bug in bt_link_release
run #7: crashed: WARNING: ODEBUG bug in bt_link_release
run #8: crashed: WARNING: ODEBUG bug in bt_link_release
run #9: crashed: WARNING: ODEBUG bug in bt_link_release
revisions tested: 2, total time: 25m38.097187099s (build: 18m42.250102879s, test: 6m21.808119752s)
the crash still happens on HEAD
commit msg: Linux 4.14.210
crash: WARNING: ODEBUG bug in bt_link_release
Bluetooth: hci3 command 0x0419 tx timeout
Bluetooth: hci4 command 0x0419 tx timeout
Bluetooth: hci5 command 0x0419 tx timeout
ODEBUG: free active (active state 0) object type: work_struct hint: hci_conn_timeout+0x0/0x200 include/linux/list.h:63
------------[ cut here ]------------
WARNING: CPU: 1 PID: 7191 at lib/debugobjects.c:290 debug_print_object.cold.8+0xa7/0xdb lib/debugobjects.c:287
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 7191 Comm: kworker/u5:2 Not tainted 4.14.210-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: hci0 hci_rx_work
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x14b/0x1f1 lib/dump_stack.c:58
 panic+0x1b0/0x358 kernel/panic.c:183
 __warn.cold.7+0x25/0x2c kernel/panic.c:547
 report_bug+0x1a4/0x1f3 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 do_error_trap+0x1bd/0x310 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:964
RIP: 0010:debug_print_object.cold.8+0xa7/0xdb lib/debugobjects.c:287
RSP: 0018:ffff8881cfcc7890 EFLAGS: 00010086
RAX: 000000000000005e RBX: 0000000000000003 RCX: 0000000000000000
RDX: 000000000000005e RSI: ffffffff86cbeb20 RDI: ffffed1039f98f09
RBP: ffff8881cfcc78b8 R08: 0000000000000000 R09: 0000000000000000
R10: fffffbfff13442c9 R11: dffffc0000000000 R12: ffffffff86c97d20
R13: ffffffff85c3d990 R14: 0000000000000000 R15: dffffc0000000000
 __debug_check_no_obj_freed lib/debugobjects.c:747 [inline]
 debug_check_no_obj_freed+0x4bc/0x890 lib/debugobjects.c:776
 kfree+0xbd/0x270 mm/slab.c:3814
 bt_link_release+0x10/0x20 net/bluetooth/hci_sysfs.c:14
 device_release+0xd7/0x170 drivers/base/core.c:831
 kobject_cleanup lib/kobject.c:646 [inline]
 kobject_release lib/kobject.c:675 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x10d/0x1b0 lib/kobject.c:692
 put_device+0x12/0x20 drivers/base/core.c:2014
 hci_conn_put include/net/bluetooth/hci_core.h:945 [inline]
 hci_conn_cleanup+0x2cc/0x520 net/bluetooth/hci_conn.c:134
 hci_conn_del+0x211/0x5e0 net/bluetooth/hci_conn.c:611
 hci_phy_link_complete_evt net/bluetooth/hci_event.c:4354 [inline]
 hci_event_packet+0x570b/0x70c0 net/bluetooth/hci_event.c:5442
 hci_rx_work+0x30e/0x8d0 net/bluetooth/hci_core.c:4244
 process_one_work+0x74f/0x1620 kernel/workqueue.c:2116
 worker_thread+0xcc/0xed0 kernel/workqueue.c:2250
 kthread+0x338/0x400 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

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