https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_25/fi-bsw-n3050/igt@drv_suspend@debugfs-reader.html

<4>[   14.823938] R13: ffffffffa9115b80 R14: ffff939dc574d000 R15: dead000000000100
<4>[   14.824025] FS:  00007fc828046680(0000) GS:ffff90497fc00000(0000) knlGS:0000000000000000
<4>[   14.824121] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4>[   14.824193] CR2: 00007ffd38be6f28 CR3: 0000000175ada000 CR4: 00000000001006f0
<4>[   14.824279] Call Trace:
<4>[   14.824318]  ? trace_hardirqs_on_thunk+0x1a/0x1c
<4>[   14.824385]  ? lock_acquire+0xa6/0x210
<4>[   14.824438]  ? debug_check_no_obj_freed+0xa4/0x210
<4>[   14.824506]  debug_check_no_obj_freed+0x194/0x210
<4>[   14.824574]  __vunmap+0xab/0x100
<4>[   14.824621]  load_module+0x2e2/0x2b20
<4>[   14.824677]  ? vfs_read+0x122/0x140
<4>[   14.824727]  ? kernel_read+0x27/0x40
<4>[   14.824776]  ? kernel_read_file+0xee/0x180
<4>[   14.824836]  ? __se_sys_finit_module+0xd3/0xf0
<4>[   14.824894]  __se_sys_finit_module+0xd3/0xf0
<4>[   14.824958]  do_syscall_64+0x55/0x190
<4>[   14.825009]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
<4>[   14.825074] RIP: 0033:0x7fc827b70839
<4>[   14.825122] RSP: 002b:00007ffdc72700d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
<4>[   14.825216] RAX: ffffffffffffffda RBX: 0000556090c58be0 RCX: 00007fc827b70839
<4>[   14.825303] RDX: 0000000000000000 RSI: 00007fc82784f0e5 RDI: 000000000000000f
<4>[   14.825389] RBP: 00007fc82784f0e5 R08: 0000000000000000 R09: 00007ffdc72701f0
<4>[   14.825476] R10: 000000000000000f R11: 0000000000000246 R12: 0000000000000000
<4>[   14.825561] R13: 0000556090c44a70 R14: 0000000000020000 R15: 0000556090c58be0
<4>[   14.825656] Code: 02 01 e8 2d 38 05 00 8b 43 10 4d 89 e9 4c 89 e6 8b 4b 14 4c 8b 45 00 48 c7 c7 b8 72 0a aa 48 8b 14 c5 60 44 e4 a9 e8 89 76 bf ff <0f> 0b 48 c7 c7 f8 72 0a aa e8 64 ce c6 ff be 02 00 00 00 48 89 
<4>[   14.825980] irq event stamp: 237344
<4>[   14.826028] hardirqs last  enabled at (237343): [<ffffffffa994756c>] _raw_spin_unlock_irqrestore+0x4c/0x60
<4>[   14.826144] hardirqs last disabled at (237344): [<ffffffffa99473dd>] _raw_spin_lock_irqsave+0xd/0x50
<4>[   14.826254] softirqs last  enabled at (236608): [<ffffffffa9c0032b>] __do_softirq+0x32b/0x4e1
<4>[   14.826358] softirqs last disabled at (236589): [<ffffffffa908f594>] irq_exit+0xa4/0xb0
<4>[   14.826454] WARNING: CPU: 0 PID: 191 at lib/debugobjects.c:339 debug_print_object+0xd7/0x100
<4>[   14.826556] ---[ end trace 15bac3dd9b505041 ]---
<3>[   14.826614] ODEBUG: ODEBUG: debug object originally initialized at:
<4>[   14.826695]    schedule_timeout+0x76/0x540
<4>[   14.826749]    msleep+0x33/0x40
<4>[   14.826804]    alc283_init+0xf1/0x120 [snd_hda_codec_realtek]
<4>[   14.826883]    alc_init+0x1f/0x580 [snd_hda_codec_realtek]
<4>[   14.826964]    snd_hda_codec_build_controls+0x32/0x200 [snd_hda_codec]
<4>[   14.830705]    hda_codec_driver_probe+0xc1/0x100 [snd_hda_codec]
<4>[   14.834468]    driver_probe_device+0x306/0x480
<4>[   14.838229]    __driver_attach+0xb7/0xe0
<7>[   14.841891] [drm:do_gmbus_xfer [i915]] GMBUS [i915 gmbus panel] NAK for addr: 0040 w(1)
<4>[   14.841980]    bus_for_each_dev+0x74/0xc0
<4>[   14.841986]    bus_add_driver+0x15f/0x250
<7>[   14.845994] [drm:do_gmbus_xfer [i915]] GMBUS [i915 gmbus panel] NAK on first message, retry
<4>[   14.849812]    driver_register+0x52/0xc0
<4>[   14.849815]    do_one_initcall+0x58/0x370
<4>[   14.849818]    do_init_module+0x56/0x1ea
<4>[   14.849820]    load_module+0x2435/0x2b20
<4>[   14.849825]    __se_sys_finit_module+0xd3/0xf0
<7>[   14.869150] [drm:do_gmbus_xfer [i915]] GMBUS [i915 gmbus panel] NAK for addr: 0040 w(1)
<7>[   14.869163] [drm:drm_dp_dual_mode_detect] DP dual mode HDMI ID:  (err -6)
<4>[   14.872993]    do_syscall_64+0x55/0x190
<4>[   14.872996]    entry_SYSCALL_64_after_hwframe+0x49/0xbe
<4>[   14.873001] 
<4>[   14.873002] ============================================
<4>[   14.873003] WARNING: possible recursive locking detected
<4>[   14.873004] 4.17.0-rc1-gb463d8719fbd-drmtip_25+ #1 Not tainted
<4>[   14.873005] --------------------------------------------
<4>[   14.873006] systemd-udevd/191 is trying to acquire lock:
<4>[   14.873007] 000000007e183d4e (&obj_hash[i].lock){-.-.}, at: debug_object_activate+0xb1/0x240
<4>[   14.873015] 
<4>[   14.873015] but task is already holding lock:
<4>[   14.873016] 000000004e1b65db (&obj_hash[i].lock){-.-.}, at: debug_check_no_obj_freed+0xa4/0x210
<4>[   14.873019] 
<4>[   14.873020] other info that might help us debug this:
<4>[   14.873021]  Possible unsafe locking scenario:
<4>[   14.873022] 
<4>[   14.873022]        CPU0
<4>[   14.873023]        ----
<4>[   14.873024]   lock(&obj_hash[i].lock);
<4>[   14.873026]   lock(&obj_hash[i].lock);
<4>[   14.873027] 
<4>[   14.873028]  *** DEADLOCK ***
<4>[   14.873029] 
<4>[   14.873030]  May be due to missing lock nesting notation
<4>[   14.873030] 
<4>[   14.873031] 4 locks held by systemd-udevd/191:
<4>[   14.873032]  #0: 000000004e1b65db (&obj_hash[i].lock){-.-.}, at: debug_check_no_obj_freed+0xa4/0x210
<4>[   14.873035]  #1: 0000000025454144 (console_lock){+.+.}, at: vprintk_emit+0x22e/0x4d0
<4>[   14.873039]  #2: 0000000095423f07 (console_owner){-...}, at: console_unlock+0x150/0x640
<4>[   14.873043]  #3: 0000000001232d4c (printing_lock){....}, at: vt_console_print+0x73/0x410
<4>[   14.873046] 
<4>[   14.873047] stack backtrace:
<4>[   14.873048] CPU: 0 PID: 191 Comm: systemd-udevd Not tainted 4.17.0-rc1-gb463d8719fbd-drmtip_25+ #1
<4>[   14.873050] Hardware name:  /NUC5CPYB, BIOS PYBSWCEL.86A.0058.2016.1102.1842 11/02/2016
<4>[   14.873050] Call Trace:
<4>[   14.873051]  dump_stack+0x67/0x9b
<4>[   14.873052]  __lock_acquire+0xc67/0x1b50
<4>[   14.873053]  ? __kernel_text_address+0x9/0x30
<4>[   14.873053]  ? lockdep_on+0x20/0x20
<4>[   14.873054]  ? lock_acquire+0xa6/0x210
<4>[   14.873055]  lock_acquire+0xa6/0x210
<4>[   14.873056]  ? debug_object_activate+0xb1/0x240
<4>[   14.873057]  _raw_spin_lock_irqsave+0x33/0x50
<4>[   14.873057]  ? debug_object_activate+0xb1/0x240
<4>[   14.873058]  debug_object_activate+0xb1/0x240
<4>[   14.873059]  ? __queue_work+0x4a/0x610
<4>[   14.873060]  __queue_work+0x4a/0x610
<4>[   14.873061]  queue_work_on+0x60/0x70
<4>[   14.873061]  soft_cursor+0x1f4/0x220
<4>[   14.873062]  bit_cursor+0x51d/0x5e0
<4>[   14.873063]  ? update_attr.isra.0+0x80/0x80
<4>[   14.873064]  ? fbcon_cursor+0x123/0x1a0
<4>[   14.873064]  hide_cursor+0x25/0xa0
<4>[   14.873065]  vt_console_print+0x3fc/0x410
<4>[   14.873066]  console_unlock+0x43b/0x640
<4>[   14.873067]  vprintk_emit+0x23b/0x4d0
<4>[   14.873068]  ? collect_expired_timers+0xa0/0xa0
<4>[   14.873068]  __warn_printk+0x65/0x90
<4>[   14.873069]  ? collect_expired_timers+0xa0/0xa0
<4>[   14.873070]  debug_print_object+0xd7/0x100
<4>[   14.873071]  ? trace_hardirqs_on_thunk+0x1a/0x1c
<4>[   14.873072]  ? lock_acquire+0xa6/0x210
<4>[   14.873073]  ? debug_check_no_obj_freed+0xa4/0x210
<4>[   14.873073]  debug_check_no_obj_freed+0x194/0x210
<4>[   14.873074]  __vunmap+0xab/0x100
<4>[   14.873075]  load_module+0x2e2/0x2b20
<4>[   14.873076]  ? vfs_read+0x122/0x140
<4>[   14.873077]  ? kernel_read+0x27/0x40
<4>[   14.873077]  ? kernel_read_file+0xee/0x180
<4>[   14.873078]  ? __se_sys_finit_module+0xd3/0xf0
<4>[   14.873079]  __se_sys_finit_module+0xd3/0xf0
<4>[   14.873080]  do_syscall_64+0x55/0x190
<4>[   14.873081]  entry_SYSCALL_64_after_hwframe+0x49/0xbe