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<base href="https://bugs.freedesktop.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [BAT][SKL GUC only] igt@debugfs_test@read_all_entries - dmesg-warn - WARNING: possible circular locking dependency detected"
href="https://bugs.freedesktop.org/show_bug.cgi?id=104693">104693</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[BAT][SKL GUC only] igt@debugfs_test@read_all_entries - dmesg-warn - WARNING: possible circular locking dependency detected
</td>
</tr>
<tr>
<th>Product</th>
<td>DRI
</td>
</tr>
<tr>
<th>Version</th>
<td>DRI git
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Other
</td>
</tr>
<tr>
<th>OS</th>
<td>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>marta.lofstedt@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>Starting at CI_DRM_3648 on the SKL GUC machine, lockdep:
<a href="https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_3648/fi-skl-guc/igt@debugfs_test@read_all_entries.html">https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_3648/fi-skl-guc/igt@debugfs_test@read_all_entries.html</a>
[ 30.062893] ======================================================
[ 30.062894] WARNING: possible circular locking dependency detected
[ 30.062895] 4.15.0-rc8-CI-CI_DRM_3648+ #1 Tainted: G U
[ 30.062896] ------------------------------------------------------
[ 30.062897] debugfs_test/1268 is trying to acquire lock:
[ 30.062898] (&dev->struct_mutex){+.+.}, at: [<00000000e4213449>]
i915_mutex_lock_interruptible+0x47/0x130 [i915]
[ 30.062921]
but task is already holding lock:
[ 30.062921] (&mm->mmap_sem){++++}, at: [<00000000dd7adc93>]
__do_page_fault+0x106/0x560
[ 30.062924]
which lock already depends on the new lock.
[ 30.062925]
the existing dependency chain (in reverse order) is:
[ 30.062926]
-> #3 (&mm->mmap_sem){++++}:
[ 30.062930] _copy_to_user+0x1e/0x70
[ 30.062932] filldir+0x8c/0xf0
[ 30.062934] dcache_readdir+0xeb/0x160
[ 30.062935] iterate_dir+0xdc/0x140
[ 30.062936] SyS_getdents+0xa0/0x130
[ 30.062938] entry_SYSCALL_64_fastpath+0x22/0x8f
[ 30.062939]
-> #2 (&sb->s_type->i_mutex_key#3){++++}:
[ 30.062942] start_creating+0x59/0x110
[ 30.062944] __debugfs_create_file+0x2e/0xe0
[ 30.062946] relay_create_buf_file+0x62/0x80
[ 30.062947] relay_late_setup_files+0x84/0x250
[ 30.062967] guc_log_late_setup+0x52/0x110 [i915]
[ 30.062985] i915_guc_log_register+0x3a/0x60 [i915]
[ 30.062997] i915_driver_load+0x7b6/0x1720 [i915]
[ 30.063014] i915_pci_probe+0x2e/0x90 [i915]
[ 30.063017] pci_device_probe+0x9c/0x120
[ 30.063018] driver_probe_device+0x2a3/0x480
[ 30.063020] __driver_attach+0xd9/0xe0
[ 30.063021] bus_for_each_dev+0x57/0x90
[ 30.063022] bus_add_driver+0x168/0x260
[ 30.063023] driver_register+0x52/0xc0
[ 30.063024] do_one_initcall+0x39/0x150
[ 30.063025] do_init_module+0x56/0x1ef
[ 30.063026] load_module+0x231c/0x2d70
[ 30.063027] SyS_finit_module+0xa5/0xe0
[ 30.063028] do_syscall_64+0x59/0x1a0
[ 30.063030] return_from_SYSCALL_64+0x0/0x75
[ 30.063030]
-> #1 (relay_channels_mutex){+.+.}:
[ 30.063034] relay_open+0x12c/0x2b0
[ 30.063051] guc_log_runtime_create+0xa0/0x220 [i915]
[ 30.063067] intel_guc_log_create+0xec/0x1c0 [i915]
[ 30.063083] intel_guc_init+0x5d/0x100 [i915]
[ 30.063100] intel_uc_init+0x29/0xa0 [i915]
[ 30.063116] i915_gem_init+0x18a/0x540 [i915]
[ 30.063128] i915_driver_load+0xaa9/0x1720 [i915]
[ 30.063140] i915_pci_probe+0x2e/0x90 [i915]
[ 30.063141] pci_device_probe+0x9c/0x120
[ 30.063143] driver_probe_device+0x2a3/0x480
[ 30.063144] __driver_attach+0xd9/0xe0
[ 30.063145] bus_for_each_dev+0x57/0x90
[ 30.063146] bus_add_driver+0x168/0x260
[ 30.063147] driver_register+0x52/0xc0
[ 30.063148] do_one_initcall+0x39/0x150
[ 30.063149] do_init_module+0x56/0x1ef
[ 30.063150] load_module+0x231c/0x2d70
[ 30.063151] SyS_finit_module+0xa5/0xe0
[ 30.063152] do_syscall_64+0x59/0x1a0
[ 30.063153] return_from_SYSCALL_64+0x0/0x75
[ 30.063154]
-> #0 (&dev->struct_mutex){+.+.}:
[ 30.063156] __mutex_lock+0x81/0x9b0
[ 30.063172] i915_mutex_lock_interruptible+0x47/0x130 [i915]
[ 30.063187] i915_gem_fault+0x201/0x790 [i915]
[ 30.063190] __do_fault+0x15/0x70
[ 30.063191] __handle_mm_fault+0x677/0xdc0
[ 30.063193] handle_mm_fault+0x14f/0x2f0
[ 30.063194] __do_page_fault+0x2d1/0x560
[ 30.063195] page_fault+0x4c/0x60
[ 30.063196]
other info that might help us debug this:
[ 30.063197] Chain exists of:
&dev->struct_mutex --> &sb->s_type->i_mutex_key#3 -->
&mm->mmap_sem
[ 30.063200] Possible unsafe locking scenario:
[ 30.063201] CPU0 CPU1
[ 30.063201] ---- ----
[ 30.063202] lock(&mm->mmap_sem);
[ 30.063203] lock(&sb->s_type->i_mutex_key#3);
[ 30.063205] lock(&mm->mmap_sem);
[ 30.063206] lock(&dev->struct_mutex);
[ 30.063207]
*** DEADLOCK ***
[ 30.063208] 1 lock held by debugfs_test/1268:
[ 30.063209] #0: (&mm->mmap_sem){++++}, at: [<00000000dd7adc93>]
__do_page_fault+0x106/0x560
[ 30.063211]
stack backtrace:
[ 30.063213] CPU: 4 PID: 1268 Comm: debugfs_test Tainted: G U
4.15.0-rc8-CI-CI_DRM_3648+ #1
[ 30.063214] Hardware name: System manufacturer System Product Name/Z170 PRO
GAMING, BIOS 3402 04/26/2017
[ 30.063214] Call Trace:
[ 30.063216] dump_stack+0x5f/0x86
[ 30.063219] print_circular_bug.isra.18+0x1d0/0x2c0
[ 30.063221] __lock_acquire+0x14ae/0x1b60
[ 30.063224] ? lock_acquire+0xaf/0x200
[ 30.063226] lock_acquire+0xaf/0x200
[ 30.063240] ? i915_mutex_lock_interruptible+0x47/0x130 [i915]
[ 30.063242] __mutex_lock+0x81/0x9b0
[ 30.063256] ? i915_mutex_lock_interruptible+0x47/0x130 [i915]
[ 30.063270] ? i915_mutex_lock_interruptible+0x47/0x130 [i915]
[ 30.063285] ? i915_mutex_lock_interruptible+0x47/0x130 [i915]
[ 30.063298] i915_mutex_lock_interruptible+0x47/0x130 [i915]
[ 30.063300] ? __pm_runtime_resume+0x4f/0x80
[ 30.063315] i915_gem_fault+0x201/0x790 [i915]
[ 30.063317] __do_fault+0x15/0x70
[ 30.063318] ? _raw_spin_unlock+0x29/0x40
[ 30.063320] __handle_mm_fault+0x677/0xdc0
[ 30.063323] handle_mm_fault+0x14f/0x2f0
[ 30.063324] __do_page_fault+0x2d1/0x560
[ 30.063326] ? page_fault+0x36/0x60
[ 30.063327] page_fault+0x4c/0x60
[ 30.063328] RIP: 0033:0x7f6675e9ae4f
[ 30.063329] RSP: 002b:00007ffc3ed48868 EFLAGS: 00010283</pre>
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