Bug 108690

Summary:	[CI][SHARDS] igt@gem_exec_reuse@baggage - dmesg-warn - ODEBUG: Out of memory. ODEBUG disabled
Product:	DRI	Reporter:	Martin Peres <martin.peres>
Component:	DRM/Intel	Assignee:	Intel GFX Bugs mailing list <intel-gfx-bugs>
Status:	CLOSED FIXED	QA Contact:	Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity:	normal
Priority:	high	CC:	intel-gfx-bugs
Version:	XOrg git
Hardware:	Other
OS:	All
Whiteboard:	ReadyForDev
i915 platform:	BXT	i915 features:	GEM/Other

Description Martin Peres 2018-11-07 15:13:09 UTC

https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_5096/shard-apl8/igt@gem_exec_reuse@baggage.html

<6> [630.362731] [IGT] gem_exec_reuse: starting subtest baggage
<6> [682.800570] [IGT] gem_exec_reuse: exiting, ret=0
<6> [685.973846] Console: switching to colour frame buffer device 240x67
<4> [697.383196] ODEBUG: Out of memory. ODEBUG disabled
<4> [698.591841] stack segment: 0000 [#1] PREEMPT SMP NOPTI
<4> [698.591905] CPU: 0 PID: 12 Comm: kworker/0:1 Tainted: G     U            4.20.0-rc1-CI-CI_DRM_5096+ #1
<4> [698.591974] Hardware name:  /NUC6CAYB, BIOS AYAPLCEL.86A.0049.2018.0508.1356 05/08/2018
<4> [698.592041] Workqueue: events free_obj_work
<4> [698.592078] RIP: 0010:free_obj_work+0x143/0x210
<4> [698.592116] Code: dd 00 00 00 49 bd 00 01 00 00 00 00 ad de 49 bc 00 02 00 00 00 00 ad de 48 89 43 08 4c 89 2e 4c 89 66 08 e8 3f 0e d6 ff eb 16 <48> 89 45 08 48 89 de 4c 89 2b 4c 89 63 08 48 89 eb e8 27 0e d6 ff
<4> [698.592247] RSP: 0018:ffffc9000007fe30 EFLAGS: 00010202
<4> [698.592288] RAX: ffffc9000007fe30 RBX: ffff8801529c5d68 RCX: 0000000000000001
<4> [698.592342] RDX: 0000000080000001 RSI: 00000000ffffffff RDI: ffff880276816a80
<4> [698.592395] RBP: 6b6b6b6b6b6b6b6b R08: 0000000000000000 R09: 0000000000000001
<4> [698.592448] R10: 0000000000000000 R11: 0000000000000000 R12: dead000000000200
<4> [698.592500] R13: dead000000000100 R14: 0000000000000000 R15: 0000000000000000
<4> [698.592554] FS:  0000000000000000(0000) GS:ffff880277a00000(0000) knlGS:0000000000000000
<4> [698.592614] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4> [698.592658] CR2: 0000564ee3e10f28 CR3: 000000026e5c4000 CR4: 00000000003406f0
<4> [698.592711] Call Trace:
<4> [698.592740]  process_one_work+0x262/0x630
<4> [698.592779]  worker_thread+0x37/0x380
<4> [698.592812]  ? process_one_work+0x630/0x630
<4> [698.592847]  kthread+0x119/0x130
<4> [698.592876]  ? kthread_park+0x80/0x80
<4> [698.592911]  ret_from_fork+0x3a/0x50
<4> [698.592947] Modules linked in: vgem snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic i915 x86_pkg_temp_thermal coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core lpc_ich snd_pcm r8169 mei_me prime_numbers mei pinctrl_broxton pinctrl_intel

Comment 1 Chris Wilson 2018-11-07 15:27:25 UTC

I get the feeling that rc1 brought in a slew of new debugobject users, too many for the debugobject preallocation to handle. The current preallocation code dates from Feb 2018 so unlikely to be behind the recent discovery.

Comment 2 Chris Wilson 2018-11-08 09:25:18 UTC

I wonder if we've enabled rcu debug objects recently. That ties in with the recent reports for untracked rcu objects on what seems to be an old problem.

Comment 3 Chris Wilson 2018-11-08 09:27:53 UTC

Something else to note is that the debugobject preallocation is done in debug_object_init, and so if we have not been calling them for our obj->rcu that's a lot of debugobjects being allocated without any preallocation!

Comment 4 Chris Wilson 2018-11-09 10:47:57 UTC

commit 8811d616dfaa8c6e1905a20ce0543ec401275997 (HEAD -> drm-intel-next-queued, drm-intel/for-linux-next, drm-intel/drm-intel-next-queued)
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Nov 9 09:03:11 2018 +0000

    drm/i915: Initialise the obj->rcu head
    
    Make the rcu_head known to the system, in particular for debugobjects.
    And having declared it for debugobjects, we need to tidy up afterwards.
    
    v2: mark the obj->rcu as being destroyed when we reuse its location for
    the freed list.
    
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108691
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
    Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
    Link: https://patchwork.freedesktop.org/patch/msgid/20181109090311.15321-1-chris@chris-wilson.co.uk

Comment 5 Martin Peres 2018-11-13 15:40:13 UTC

This indeed fixed it, thanks!

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