bisecting fixing commit since ddef1e8e3f6eb26034833b7255e3fa584d54a230 building syzkaller on c9610487d8c10f7b4ffb32764a6720cbbdfe6058 testing commit ddef1e8e3f6eb26034833b7255e3fa584d54a230 with gcc (GCC) 8.1.0 kernel signature: 64bcba2c57bc2938cf63b7299859478f694ee3c8 all runs: crashed: WARNING: ODEBUG bug in rfcomm_dlc_free testing current HEAD a844dc4c544291470aa69edbe2434b040794e269 testing commit a844dc4c544291470aa69edbe2434b040794e269 with gcc (GCC) 8.1.0 kernel signature: 872ded1eee03a9bc12a25b5b1efb68a86acc690d all runs: crashed: WARNING: ODEBUG bug in rfcomm_dlc_free revisions tested: 2, total time: 23m1.006167643s (build: 15m50.237439002s, test: 6m41.701547731s) the crash still happens on HEAD commit msg: Linux 4.14.158 crash: WARNING: ODEBUG bug in rfcomm_dlc_free ODEBUG: free active (active state 0) object type: timer_list hint: rfcomm_dlc_timeout+0x0/0x50 include/linux/list.h:64 IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_hsr: link becomes ready ------------[ cut here ]------------ IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready WARNING: CPU: 1 PID: 6790 at lib/debugobjects.c:290 debug_print_object.cold.13+0xa7/0xdb lib/debugobjects.c:287 IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_team: link becomes ready Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 6790 Comm: syz-executor.2 Not tainted 4.14.158-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xf7/0x13b lib/dump_stack.c:58 IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready panic+0x1b0/0x358 kernel/panic.c:183 IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready __warn.cold.8+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 IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314 IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:963 8021q: adding VLAN 0 to HW filter on device batadv0 RIP: 0010:debug_print_object.cold.13+0xa7/0xdb lib/debugobjects.c:287 RSP: 0018:ffff888086317a70 EFLAGS: 00010082 RAX: 000000000000005e RBX: 0000000000000003 RCX: 0000000000000000 RDX: 000000000000005e RSI: 0000000000000001 RDI: ffffed1010c62f45 RBP: ffff888086317a98 R08: 0000000000000000 R09: 0000000000000000 R10: fffffbfff1268884 R11: ffff88809ff1a240 R12: ffffffff868ca300 R13: ffffffff85882b30 R14: 0000000000000000 R15: ffff88809856fce8 __debug_check_no_obj_freed lib/debugobjects.c:747 [inline] debug_check_no_obj_freed+0x506/0x930 lib/debugobjects.c:776 kobject: 'vlan0' (ffff8880984cf800): kobject_add_internal: parent: 'mesh', set: '' kfree+0xbd/0x270 mm/slab.c:3814 rfcomm_dlc_free+0x19/0x20 net/bluetooth/rfcomm/core.c:328 rfcomm_dlc_put include/net/bluetooth/rfcomm.h:258 [inline] __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:417 [inline] rfcomm_create_dev net/bluetooth/rfcomm/tty.c:486 [inline] rfcomm_dev_ioctl+0x1403/0x1870 net/bluetooth/rfcomm/tty.c:588 rfcomm_sock_ioctl+0x71/0xa0 net/bluetooth/rfcomm/sock.c:902 sock_do_ioctl+0x62/0xa0 net/socket.c:974 sock_ioctl+0x251/0x430 net/socket.c:1071 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x180/0xfb0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x74/0x80 fs/ioctl.c:692 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x459f49 RSP: 002b:00007fa901793c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459f49 RDX: 0000000020000100 RSI: 00000000400452c8 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa9017946d4 R13: 00000000004c2959 R14: 00000000004d68c8 R15: 00000000ffffffff ======================================================