3.5 regression on i915

[Willy Tarreau]

Chris, Daniel,

since version 3.5, my Asus EeePC 1005HA bugs during startx. I didn't
have the time to investigate until this evening.

I could bisect the commits and found that the following one was merged
in 3.5-rc1 and is responsible for these bugs that can reliably be
triggered :

  1b50247a8ddde4af5aaa0e6bc125615372ce6c16 is the first bad commit
  commit 1b50247a8ddde4af5aaa0e6bc125615372ce6c16
  Author: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
  Date:   Tue Apr 24 15:47:30 2012 +0100

    drm/i915: Remove the list of pinned inactive objects
    
    Simplify object tracking by removing the inactive but pinned list. The
    only place where this was used is for counting the available memory,
    which is just as easy performed by checking all objects on the rare
    occasions it is required (application startup). For ease of debugging,
    we keep the reporting of pinned objects through the error-state and
    debugfs.
    
    Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
    Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>

I tried to revert it from 3.5.6-rc1 but it does not revert cleanly at all
and I'm totall unfamiliar with this code to attempt anything sane at this
time of the night.

The crash happens here in i915_gem_entervt_ioctl() :

    3659          BUG_ON(!list_empty(&dev_priv->mm.active_list));
    3660          BUG_ON(!list_empty(&dev_priv->mm.flushing_list));
 -> 3661          BUG_ON(!list_empty(&dev_priv->mm.inactive_list));
    3662          mutex_unlock(&dev->struct_mutex);

More info in the trace below :

------------[ cut here ]------------
kernel BUG at drivers/gpu/drm/i915/i915_gem.c:3661!
invalid opcode: 0000 [#1] SMP 
Modules linked in: snd_seq_dummy snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss uvcvideo videobuf2_core videodev videobuf2_vmalloc videobuf2_memops uhci_hcd ath9k mac80211 snd_hda_codec_realtek ath9k_common microcode ath9k_hw psmouse serio_raw sg ath cfg80211 atl1c lpc_ich mfd_core ehci_hcd snd_hda_intel snd_hda_codec snd_hwdep snd_pcm rtc_cmos snd_timer snd evdev eeepc_laptop snd_page_alloc sparse_keymap

Pid: 2866, comm: X Not tainted 3.5.6-rc1-eeepc #1 ASUSTeK Computer INC. 1005HA/1005HA
EIP: 0060:[<c12dc291>] EFLAGS: 00013297 CPU: 0
EIP is at i915_gem_entervt_ioctl+0xf1/0x110
EAX: f5941df4 EBX: f5940000 ECX: 00000000 EDX: 00020000
ESI: f5835400 EDI: 00000000 EBP: f51d7e38 ESP: f51d7e20
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
CR0: 8005003b CR2: b760e0a0 CR3: 351b6000 CR4: 000007d0
DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
DR6: ffff0ff0 DR7: 00000400
Process X (pid: 2866, ti=f51d6000 task=f61af8d0 task.ti=f51d6000)
Stack:
 00000001 00000000 f5835414 f51d7e84 f5835400 f54f85c0 f51d7f10 c12b530b
 00000001 c151b139 c14751b6 c152e030 00000b32 00006459 00000059 0000e200
 00000001 00000000 00006459 c159ddd0 c12dc1a0 ffffffea 00000000 00000000
Call Trace:
 [<c12b530b>] drm_ioctl+0x2eb/0x440
 [<c12dc1a0>] ? i915_gem_init+0xe0/0xe0
 [<c1052b2b>] ? enqueue_hrtimer+0x1b/0x50
 [<c1053321>] ? __hrtimer_start_range_ns+0x161/0x330
 [<c10530b3>] ? lock_hrtimer_base+0x23/0x50
 [<c1053163>] ? hrtimer_try_to_cancel+0x33/0x70
 [<c12b5020>] ? drm_version+0x90/0x90
 [<c10ca171>] vfs_ioctl+0x31/0x50
 [<c10ca2e4>] do_vfs_ioctl+0x64/0x510
 [<c10535de>] ? hrtimer_nanosleep+0x8e/0x100
 [<c1052c20>] ? update_rmtp+0x80/0x80
 [<c10ca7c9>] sys_ioctl+0x39/0x60
 [<c1433949>] syscall_call+0x7/0xb
Code: 83 c4 0c 5b 5e 5f 5d c3 c7 44 24 04 2c 05 53 c1 c7 04 24 6f ef 47 c1 e8 6e e0 fd ff c7 83 38 1e 00 00 00 00 00 00 e9 3f ff ff ff <0f> 0b eb fe 0f 0b eb fe 8d b4 26 00 00 00 00 0f 0b eb fe 8d b6 
EIP: [<c12dc291>] i915_gem_entervt_ioctl+0xf1/0x110 SS:ESP 0068:f51d7e20
---[ end trace dd332ec083cbd513 ]---

I have the full dmesg if that can help. I do not have KMS and have not
tested 3.6-* yet.

$ grep I915 .config
CONFIG_DRM_I915=y
# CONFIG_DRM_I915_KMS is not set

Please tell me if you want more info (config, full dmesg, etc... didn't
want to pollute the list) or if you want me to test any patch. I'm willing
to help getting this issue fixed.

Thanks,
Willy

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