bisecting fixing commit since f6d5cb9e2c06f7d583dd9f4f7cca21d13d78c32a
building syzkaller on 816e0689d7d9d8321f8bf360740f0e516aee15ca
testing commit f6d5cb9e2c06f7d583dd9f4f7cca21d13d78c32a with gcc (GCC) 8.1.0
kernel signature: 674659cb1035358a2edf255344873f651d9751b4c495a8f36022d163bedd86cf
run #0: crashed: WARNING: ODEBUG bug in bt_host_release
run #1: crashed: WARNING: ODEBUG bug in bt_host_release
run #2: crashed: general protection fault in __queue_work
run #3: crashed: WARNING: ODEBUG bug in bt_host_release
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: c264a6a2ef855cf3d9898a3ef1ca6c3a009ae48593ed38956cebc9195a9ab6c8
run #0: crashed: KASAN: use-after-free Read in __queue_work
run #1: crashed: KASAN: use-after-free Read 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: 41m18.325990784s (build: 19m25.552260317s, test: 20m58.315964273s)
the crash still happens on HEAD
commit msg: Linux 4.19.163
crash: WARNING: ODEBUG bug in bt_host_release
Bluetooth: hci1: command 0x0401 tx timeout
Bluetooth: hci1: command 0x0401 tx timeout
Bluetooth: hci1: command 0x0401 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: 22700 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: 22700 Comm: syz-executor.0 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:ffff8881ed407800 EFLAGS: 00010082
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000004 RSI: 0000000000000008 RDI: ffffffff8a19ca60
RBP: ffff8881ed407840 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
 get_signal+0x308/0x1970 kernel/signal.c:2589
 do_signal+0x87/0x1860 arch/x86/kernel/signal.c:821
 exit_to_usermode_loop+0x159/0x1e0 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45d5b9
Code: Bad RIP value.
RSP: 002b:00007f6e71c92cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000118cf48 RCX: 000000000045d5b9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000118cf48
RBP: 000000000118cf40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffdf0c0c16f R14: 00007f6e71c939c0 R15: 000000000118cf4c

======================================================