bisecting fixing commit since d18b78abc0c6e7d3119367c931c583e02d466495
building syzkaller on 6436ce4bcd8e2c7dcca0b171ac91f51e96d973f8
testing commit d18b78abc0c6e7d3119367c931c583e02d466495 with gcc (GCC) 8.1.0
kernel signature: 8a22a35d3b318e9c27b21c882d0204b9f967e1b2d74a9c34dbbf58852c977e28
run #0: crashed: WARNING: ODEBUG bug in bt_host_release
run #1: crashed: WARNING: ODEBUG bug in bt_host_release
run #2: crashed: WARNING: ODEBUG bug in bt_host_release
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
reproducer seems to be flaky
testing current HEAD 13d2ce42de8cb98ff952f8de6307f896203854c2
testing commit 13d2ce42de8cb98ff952f8de6307f896203854c2 with gcc (GCC) 8.1.0
kernel signature: e82df355be3b15209abbf0bf70337cd731459757d7b7b3dcf45b4022d66e689b
run #0: crashed: WARNING: ODEBUG bug in bt_host_release
run #1: crashed: general protection fault in __queue_work
run #2: crashed: WARNING: ODEBUG bug in bt_host_release
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
Reproducer flagged being flaky
revisions tested: 2, total time: 38m29.870492431s (build: 18m53.307706975s, test: 18m41.206664067s)
the crash still happens on HEAD
commit msg: Linux 4.19.163
crash: WARNING: ODEBUG bug in bt_host_release
Bluetooth: hci0: command 0x0419 tx timeout
Bluetooth: hci0: command 0x0c1a tx timeout
Bluetooth: hci0: command 0x0c1a tx timeout
------------[ cut here ]------------
ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x90 kernel/workqueue.c:4943
WARNING: CPU: 0 PID: 20570 at lib/debugobjects.c:328 debug_print_object+0x168/0x210 lib/debugobjects.c:325
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 20570 Comm: syz-executor.5 Not tainted 4.19.163-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x17c/0x22a lib/dump_stack.c:118
 panic+0x1cd/0x375 kernel/panic.c:186
 __warn.cold.7+0x1b/0x3e kernel/panic.c:541
 report_bug+0x1a4/0x200 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x200/0x350 arch/x86/kernel/traps.c:296
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038
RIP: 0010:debug_print_object+0x168/0x210 lib/debugobjects.c:325
Code: 67 87 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 92 00 00 00 48 8b 14 dd 80 94 67 87 4c 89 fe 48 c7 c7 00 8a 67 87 e8 db 84 07 fe <0f> 0b 83 05 0b 91 f2 05 01 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffff8881e7f67aa8 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000004 RSI: 0000000000000008 RDI: ffffffff8a19ca60
RBP: ffff8881e7f67ae8 R08: ffffed103ed03eef R09: ffffed103ed03eee
R10: ffffed103ed03eee R11: ffff8881f681f777 R12: 0000000000000001
R13: ffffffff88598ec0 R14: ffffffff8153ad80 R15: ffffffff876790e0
 __debug_check_no_obj_freed lib/debugobjects.c:785 [inline]
 debug_check_no_obj_freed+0x252/0x428 lib/debugobjects.c:817
 kfree+0xbd/0x220 mm/slab.c:3821
 bt_host_release+0x10/0x20 net/bluetooth/hci_sysfs.c:86
 device_release+0x71/0x1d0 drivers/base/core.c:1061
 kobject_cleanup lib/kobject.c:662 [inline]
 kobject_release lib/kobject.c:691 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x115/0x1f0 lib/kobject.c:708
 put_device+0x12/0x20 drivers/base/core.c:2251
 hci_free_dev+0x10/0x20 net/bluetooth/hci_core.c:3145
 vhci_release+0x73/0xe0 drivers/bluetooth/hci_vhci.c:355
 __fput+0x249/0x7f0 fs/file_table.c:278
 ____fput+0x9/0x10 fs/file_table.c:309
 task_work_run+0x108/0x180 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xa8e/0x2e00 kernel/exit.c:890
 do_group_exit+0xf8/0x2c0 kernel/exit.c:993
 __do_sys_exit_group kernel/exit.c:1004 [inline]
 __se_sys_exit_group kernel/exit.c:1002 [inline]
 __x64_sys_exit_group+0x39/0x40 kernel/exit.c:1002
 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45d4d9
Code: Bad RIP value.
RSP: 002b:00007ffcf9e1b5d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045d4d9
RDX: 0000000000416d61 RSI: 00000000016a85f0 RDI: 0000000000000043
RBP: 00000000004c306d R08: 000000000000000b R09: 0000000000000000
R10: 0000000002744940 R11: 0000000000000246 R12: 0000000000000007
R13: 00007ffcf9e1b720 R14: 0000000000051c1a R15: 00007ffcf9e1b730

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