Bug 103714

Summary: [BAT] igt@vgem_basic@dmabuf-export - incomplete - BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
Product: DRI Reporter: Marta Löfstedt <marta.lofstedt>
Component: DRM/IntelAssignee: Intel GFX Bugs mailing list <intel-gfx-bugs>
Status: CLOSED FIXED QA Contact: Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity: normal    
Priority: medium CC: intel-gfx-bugs
Version: DRI git   
Hardware: Other   
OS: All   
Whiteboard: ReadyForDev
i915 platform: BYT i915 features: GEM/Other

Description Marta Löfstedt 2017-11-13 11:37:18 UTC 
https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_3338/fi-byt-n2820/igt@vgem_basic@dmabuf-export.html

<14>[  454.749693] [IGT] vgem_basic: starting subtest debugfs
<4>[  454.750315] INFO: trying to register non-static key.
<4>[  454.750330] the code is fine but needs lockdep annotation.
<4>[  454.750338] turning off the locking correctness validator.
<4>[  454.750350] CPU: 1 PID: 3939 Comm: vgem_basic Tainted: G     U          4.14.0-rc8-CI-CI_DRM_3338+ #1
<4>[  454.750365] Hardware name: ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ/DN2820FYK, BIOS FYBYT10H.86A.0059.2017.0607.2130 06/07/2017
<4>[  454.750380] Call Trace:
<4>[  454.750393]  dump_stack+0x68/0x9f
<4>[  454.750405]  register_lock_class+0x3fd/0x580
<4>[  454.750418]  ? _raw_spin_unlock+0x31/0x50
<4>[  454.750428]  ? deactivate_slab.isra.22+0x85b/0x880
<4>[  454.750439]  __lock_acquire+0xa4/0x1b00
<4>[  454.750449]  ? drm_framebuffer_info+0x48/0xc0
<4>[  454.750462]  ? kvmalloc_node+0x6f/0x80
<4>[  454.750470]  ? kvmalloc_node+0x6f/0x80
<4>[  454.750480]  ? debug_smp_processor_id+0x17/0x20
<4>[  454.750491]  lock_acquire+0xb0/0x200
<4>[  454.750499]  ? lock_acquire+0xb0/0x200
<4>[  454.750509]  ? drm_framebuffer_info+0x48/0xc0
<4>[  454.750520]  __mutex_lock+0x86/0x9b0
<4>[  454.750529]  ? drm_framebuffer_info+0x48/0xc0
<4>[  454.750539]  ? drm_framebuffer_info+0x48/0xc0
<4>[  454.750549]  ? __slab_alloc.isra.23.constprop.28+0x59/0x80
<4>[  454.750560]  ? __this_cpu_preempt_check+0x13/0x20
<4>[  454.750585]  ? kvmalloc_node+0x6f/0x80
<4>[  454.750596]  mutex_lock_nested+0x1b/0x20
<4>[  454.750606]  ? mutex_lock_nested+0x1b/0x20
<4>[  454.750615]  drm_framebuffer_info+0x48/0xc0
<4>[  454.750625]  ? drm_mode_gamma_get_ioctl+0xf0/0xf0
<4>[  454.750636]  seq_read+0xe1/0x3a0
<4>[  454.750647]  full_proxy_read+0x54/0x80
<4>[  454.750658]  __vfs_read+0x28/0x120
<4>[  454.750667]  ? putname+0x54/0x60
<4>[  454.750677]  ? rcu_read_lock_sched_held+0x7a/0x90
<4>[  454.750690]  ? entry_SYSCALL_64_fastpath+0x5/0xb1
<4>[  454.750700]  vfs_read+0xa8/0x150
<4>[  454.750709]  SyS_read+0x49/0xb0
<4>[  454.750719]  entry_SYSCALL_64_fastpath+0x1c/0xb1
<4>[  454.750731] RIP: 0033:0x7fd4633ee500
<4>[  454.750739] RSP: 002b:00007ffd6e308ab8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
<4>[  454.750753] RAX: ffffffffffffffda RBX: ffffffff81492083 RCX: 00007fd4633ee500
<4>[  454.750766] RDX: 000000000000003f RSI: 000055cc92edbc40 RDI: 0000000000000005
<4>[  454.750776] RBP: ffffc900007a7f88 R08: 0000000000000000 R09: 0000000000000000
<4>[  454.750786] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
<4>[  454.750797] R13: 000055cc92edbc40 R14: 0000000000000000 R15: 0000000000000000
<4>[  454.750812]  ? __this_cpu_preempt_check+0x13/0x20
<1>[  454.750831] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
<1>[  454.750869] IP: drm_framebuffer_info+0x77/0xc0
<6>[  454.750887] PGD 0 P4D 0 
<4>[  454.750906] Oops: 0000 [#1] PREEMPT SMP
<0>[  454.750925] Dumping ftrace buffer:
<0>[  454.750944]    (ftrace buffer empty)
<4>[  454.750961] Modules linked in: vgem snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic i915 snd_hda_intel snd_hda_codec intel_powerclamp coretemp crct10dif_pclmul snd_hwdep crc32_pclmul ghash_clmulni_intel snd_hda_core snd_pcm r8169 mii lpc_ich prime_numbers i2c_hid
<4>[  454.751085] CPU: 1 PID: 3939 Comm: vgem_basic Tainted: G     U          4.14.0-rc8-CI-CI_DRM_3338+ #1
<4>[  454.751116] Hardware name: ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ/DN2820FYK, BIOS FYBYT10H.86A.0059.2017.0607.2130 06/07/2017
<4>[  454.751159] task: ffff88012ee6cd40 task.stack: ffffc900007a4000
<4>[  454.751182] RIP: 0010:drm_framebuffer_info+0x77/0xc0
<4>[  454.751202] RSP: 0018:ffffc900007a7d68 EFLAGS: 00010286
<4>[  454.751224] RAX: 0000000000000000 RBX: fffffffffffffff8 RCX: 0000000000000001
<4>[  454.751249] RDX: 0000000080000001 RSI: 0000000000000000 RDI: 00000000ffffffff
<4>[  454.751273] RBP: ffffc900007a7da0 R08: 0000000000000000 R09: 0000000000000000
<4>[  454.751298] R10: ffffc900007a7d58 R11: ffffffff81607ef8 R12: ffff88013076a950
<4>[  454.751323] R13: ffff88013076a8c8 R14: ffffffff81ce969b R15: ffff880131b8dbc8
<4>[  454.751348] FS:  00007fd464c0b8c0(0000) GS:ffff88013fd00000(0000) knlGS:0000000000000000
<4>[  454.751378] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4>[  454.751399] CR2: 0000000000000010 CR3: 000000011be83000 CR4: 00000000001006e0
<4>[  454.751423] Call Trace:
<4>[  454.751437]  ? drm_mode_gamma_get_ioctl+0xf0/0xf0
<4>[  454.751460]  seq_read+0xe1/0x3a0
<4>[  454.751483]  full_proxy_read+0x54/0x80
<4>[  454.751503]  __vfs_read+0x28/0x120
<4>[  454.751520]  ? putname+0x54/0x60
<4>[  454.751539]  ? rcu_read_lock_sched_held+0x7a/0x90
<4>[  454.751560]  ? entry_SYSCALL_64_fastpath+0x5/0xb1
<4>[  454.751581]  vfs_read+0xa8/0x150
<4>[  454.751598]  SyS_read+0x49/0xb0
<4>[  454.751617]  entry_SYSCALL_64_fastpath+0x1c/0xb1
<4>[  454.751635] RIP: 0033:0x7fd4633ee500
<4>[  454.751653] RSP: 002b:00007ffd6e308ab8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
<4>[  454.751683] RAX: ffffffffffffffda RBX: ffffffff81492083 RCX: 00007fd4633ee500
<4>[  454.751708] RDX: 000000000000003f RSI: 000055cc92edbc40 RDI: 0000000000000005
<4>[  454.751732] RBP: ffffc900007a7f88 R08: 0000000000000000 R09: 0000000000000000
<4>[  454.751757] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
<4>[  454.751784] R13: 000055cc92edbc40 R14: 0000000000000000 R15: 0000000000000000
<4>[  454.751811]  ? __this_cpu_preempt_check+0x13/0x20
<4>[  454.751833] Code: 20 06 00 00 48 a9 f8 ff ff ff 74 63 49 8b 84 24 a8 06 00 00 49 81 c4 a8 06 00 00 49 c7 c6 9b 96 ce 81 49 39 c4 48 8d 58 f8 74 2d <8b> 53 18 48 8d 7d c8 4c 89 f6 e8 4a 5c 00 00 48 8d 7d c8 48 89 
<1>[  454.752054] RIP: drm_framebuffer_info+0x77/0xc0 RSP: ffffc900007a7d68
<4>[  454.752076] CR2: 0000000000000010
<4>[  454.752129] ---[ end trace 756020764eb0e9d4 ]---
Comment 1 Chris Wilson 2017-11-14 17:55:52 UTC 
commit 0c51ef8684e30333ee2a7cef359258d91727166b
Author: Noralf Trønnes <noralf@tronnes.org>
Date:   Tue Nov 14 00:12:01 2017 +0100

    drm/debugfs: Fix framebuffer debugfs file init
    
    The introduction of: drm/framebuffer: Add framebuffer debugfs file
    broke vgem. That patch assumed that all drivers had initialized the
    dev->mode_config.fb_lock mutex which happens in drm_mode_config_init().
    vgem doesn't need to call drm_mode_config_init().
    
    Fix this by only creating the framebuffer debugfs file for modesetting
    drivers.
    
    Fixes: 45d58b40292b ("drm/framebuffer: Add framebuffer debugfs file")
    Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
    Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
    Reviewed-by: Dave Airlie <airlied@redhat.com>
    Signed-off-by: Jani Nikula <jani.nikula@intel.com>
    Link: https://patchwork.freedesktop.org/patch/msgid/20171113231201.26177-1-noralf@tronnes.org

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