bisecting fixing commit since d18b78abc0c6e7d3119367c931c583e02d466495 building syzkaller on 6436ce4bcd8e2c7dcca0b171ac91f51e96d973f8 testing commit d18b78abc0c6e7d3119367c931c583e02d466495 with gcc (GCC) 8.4.1 20210217 kernel signature: 66e7adc81a938829d0dfa6c395fc8758eb30ccbbc150fe15f0fb8b5e3a0c14c5 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: crashed: WARNING: ODEBUG bug in bt_host_release run #4: crashed: WARNING: ODEBUG bug in bt_host_release run #5: crashed: general protection fault in __queue_work run #6: crashed: WARNING: ODEBUG bug in bt_host_release run #7: OK run #8: crashed: WARNING: ODEBUG bug in bt_host_release run #9: OK run #10: OK run #11: OK run #12: OK run #13: OK run #14: OK run #15: OK run #16: OK run #17: OK run #18: OK run #19: OK reproducer seems to be flaky testing current HEAD 2d19be4653f5e74ed95560b69f94eb6791d49af3 testing commit 2d19be4653f5e74ed95560b69f94eb6791d49af3 with gcc (GCC) 8.4.1 20210217 kernel signature: 8c4a497c2b4b958a28ae59c077f6caddfc09d5f8c509f4f01b8a3967219adb65 run #0: crashed: KASAN: use-after-free Read in __queue_work run #1: crashed: general protection fault in __queue_work run #2: crashed: general protection fault in __queue_work run #3: crashed: KASAN: use-after-free Read in __queue_work run #4: crashed: WARNING: ODEBUG bug in bt_host_release run #5: crashed: WARNING: ODEBUG bug in bt_host_release run #6: OK run #7: OK run #8: OK run #9: OK run #10: OK run #11: OK run #12: OK run #13: OK run #14: OK run #15: OK run #16: OK run #17: OK run #18: OK run #19: OK Reproducer flagged being flaky revisions tested: 2, total time: 35m39.451727308s (build: 16m26.580483675s, test: 18m8.395232829s) the crash still happens on HEAD commit msg: Linux 4.19.177 crash: WARNING: ODEBUG bug in bt_host_release Bluetooth: hci3: command 0x0419 tx timeout ------------[ cut here ]------------ ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x90 kernel/workqueue.c:4947 WARNING: CPU: 0 PID: 17084 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: 17084 Comm: syz-executor.1 Not tainted 4.19.177-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/0x226 lib/dump_stack.c:118 panic+0x1cd/0x375 kernel/panic.c:186 __warn.cold.7+0x1b/0x36 kernel/panic.c:541 report_bug+0x1a1/0x200 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] fixup_bug arch/x86/kernel/traps.c:173 [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 e0 95 67 87 4c 89 fe 48 c7 c7 60 8b 67 87 e8 27 d0 96 03 <0f> 0b 83 05 8b a6 fa 05 01 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffff8881cebaf7d8 EFLAGS: 00010086 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000 RDX: 0000000000000004 RSI: 0000000000000008 RDI: ffffffff8a19eaa0 RBP: ffff8881cebaf818 R08: ffffed103ed03eef R09: ffffed103ed03eee R10: ffffed103ed03eee R11: ffff8881f681f777 R12: 0000000000000001 R13: ffffffff88599040 R14: ffffffff81517b40 R15: ffffffff87679240 __debug_check_no_obj_freed lib/debugobjects.c:785 [inline] debug_check_no_obj_freed+0x252/0x430 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:1076 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:2266 hci_dev_put include/net/bluetooth/hci_core.h:1009 [inline] hci_dev_cmd+0x26a/0x6b0 net/bluetooth/hci_core.c:1978 hci_sock_ioctl+0x4b2/0x600 net/bluetooth/hci_sock.c:1045 sock_do_ioctl+0xd9/0x230 net/socket.c:950 sock_ioctl+0x281/0x500 net/socket.c:1074 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465029 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd664afd188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055cfa0 RCX: 0000000000465029 RDX: 0000000020000040 RSI: 00000000400448dd RDI: 0000000000000004 RBP: 00000000004af6d2 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055cfa0 R13: 00007fffc1713d4f R14: 00007fd664afd300 R15: 0000000000022000 ======================================================