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      <base href="https://bugs.freedesktop.org/" />
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [HSW]igt/drv_module_reload causes call trace"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=86181">86181</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>[HSW]igt/drv_module_reload causes call trace
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>DRI
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux (All)
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>medium
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>DRM/Intel
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>intel-gfx-bugs@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>huax.lu@intel.com
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>intel-gfx-bugs@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>intel-gfx-bugs@lists.freedesktop.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=109316" name="attach_109316" title="dmesg">attachment 109316</a> <a href="attachment.cgi?id=109316&action=edit" title="dmesg">[details]</a></span>
dmesg

==System Environment==
--------------------------
Regression: not sure, it also has <a class="bz_bug_link 
          bz_status_VERIFIED  bz_closed"
   title="VERIFIED FIXED - [all Regression]igt/drv_module_reload causes "WARNING: CPU: 5 PID: 3993 at drivers/gpu/drm/i915/i915_irq.c:154 ironlake_disable_vblank+0x40/0x52 [i915]()""
   href="show_bug.cgi?id=83868">bug 83868</a>
Non-working platforms: HSW

==kernel==
--------------------------
drm-intel-nightly/de6d6ca380bba4f962f942089b0a212d9b3977c1

==Bug detailed description==
-----------------------------
It only happens one HSW machine(same as <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [HSW]igt/kms_setmode/clone-exclusive-crtc causes system hang"
   href="show_bug.cgi?id=85541">bug 85541</a>, <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [HSW]igt/kms_flip/flip-vs-modeset-vs-hang-interruptible causes system hang"
   href="show_bug.cgi?id=85787">bug 85787</a>, <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [HSW]igt/kms_pipe_crc_basic/hang-read-crc-pipe-B causes system hang"
   href="show_bug.cgi?id=85885">bug 85885</a>).

Clean boot system, run ./drv_module_reload, it reports call trace(the call
trace looks like <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [HSW]igt/kms_pipe_crc_basic/hang-read-crc-pipe-B causes system hang"
   href="show_bug.cgi?id=85885">bug 85885</a>).
then run dmesg -c and run ./drv_module_reload, it doesn't have call trace.

output:
unbinding /sys/class/vtconsole/vtcon0/: (M) frame buffer device
module successfully unloaded
module successfully loaded again

[   46.460577] ======================================================
[   46.460577] [ INFO: possible circular locking dependency detected ]
[   46.460578] 3.18.0-rc3_drm-intel-nightly_de6d6c_20141111_debug+ #1416 Not
tainted
[   46.460579] -------------------------------------------------------
[   46.460579] drv_module_relo/4038 is trying to acquire lock:
[   46.460585]  (console_lock){+.+.+.}, at: [<ffffffff8142ced1>]
store_bind+0x1f0/0x221
[   46.460585]
but task is already holding lock:
[   46.460588]  (s_active#16){++++.+}, at: [<ffffffff811a0756>]
kernfs_fop_write+0xaf/0x132
[   46.460588]
which lock already depends on the new lock.

[   46.460589]
the existing dependency chain (in reverse order) is:
[   46.460590]
-> #1 (s_active#16){++++.+}:
[   46.460592]        [<ffffffff81075c74>] lock_acquire+0xd3/0x10d
[   46.460594]        [<ffffffff8119efda>] __kernfs_remove+0x132/0x285
[   46.460595]        [<ffffffff8119fe23>] kernfs_remove_by_name_ns+0x70/0x8e
[   46.460596]        [<ffffffff811a1354>] sysfs_remove_file_ns+0x15/0x17
[   46.460598]        [<ffffffff8144a200>] device_remove_file+0x19/0x1b
[   46.460600]        [<ffffffff8142b56d>] do_unregister_con_driver+0x60/0xdd
[   46.460618]        [<ffffffffa011902a>] i915_driver_load+0x5c7/0xe59 [i915]
[   46.460625]        [<ffffffffa0013cf7>] drm_dev_register+0x84/0xfd [drm]
[   46.460630]        [<ffffffffa0016380>] drm_get_pci_dev+0xff/0x1b6 [drm]
[   46.460634]        [<ffffffffa00942f2>] i915_pci_probe+0x45/0x4e [i915]
[   46.460637]        [<ffffffff813bcb18>] local_pci_probe+0x3d/0x83
[   46.460638]        [<ffffffff813bcdef>] pci_device_probe+0xcb/0xf1
[   46.460640]        [<ffffffff8144dc3a>] driver_probe_device+0xa6/0x1d7
[   46.460641]        [<ffffffff8144ddce>] __driver_attach+0x63/0x87
[   46.460642]        [<ffffffff8144c29a>] bus_for_each_dev+0x5f/0x91
[   46.460643]        [<ffffffff8144d7a9>] driver_attach+0x1e/0x20
[   46.460644]        [<ffffffff8144d437>] bus_add_driver+0xf6/0x1db
[   46.460646]        [<ffffffff8144e4dc>] driver_register+0x8c/0xc3
[   46.460647]        [<ffffffff813bcee4>] __pci_register_driver+0x62/0x67
[   46.460652]        [<ffffffffa001648f>] drm_pci_init+0x58/0xd9 [drm]
[   46.460653]        [<ffffffffa017108a>] 0xffffffffa017108a
[   46.460655]        [<ffffffff8100031d>] do_one_initcall+0xef/0x18e
[   46.460656]        [<ffffffff810a68ab>] load_module+0x1a91/0x1d98
[   46.460657]        [<ffffffff810a6c59>] SyS_init_module+0xa7/0xb6
[   46.460659]        [<ffffffff81842552>] system_call_fastpath+0x12/0x17
[   46.460660]
-> #0 (console_lock){+.+.+.}:
[   46.460661]        [<ffffffff8107500d>] __lock_acquire+0x10ac/0x1803
[   46.460662]        [<ffffffff81075c74>] lock_acquire+0xd3/0x10d
[   46.460664]        [<ffffffff81081579>] console_lock+0x41/0x60
[   46.460665]        [<ffffffff8142ced1>] store_bind+0x1f0/0x221
[   46.460666]        [<ffffffff81449a80>] dev_attr_store+0x18/0x24
[   46.460667]        [<ffffffff811a14fb>] sysfs_kf_write+0x4a/0x52
[   46.460668]        [<ffffffff811a0790>] kernfs_fop_write+0xe9/0x132
[   46.460670]        [<ffffffff8113c7f4>] vfs_write+0xbe/0x19a
[   46.460672]        [<ffffffff8113cafe>] SyS_write+0x4a/0x91
[   46.460673]        [<ffffffff81842552>] system_call_fastpath+0x12/0x17
[   46.460673]
other info that might help us debug this:


==Reproduce steps==
---------------------------- 
1. clean boot system
2. ./drv_module_reload</pre>
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