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<base href="https://bugs.freedesktop.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [PSTORE] Deadlock detected with lockdep when # rm /sys/fs/pstore/*"
href="https://bugs.freedesktop.org/show_bug.cgi?id=100234">100234</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[PSTORE] Deadlock detected with lockdep when # rm /sys/fs/pstore/*
</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>Keywords</th>
<td>notourbug
</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>tomi.p.sarvela@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>
<tr>
<th>i915 platform</th>
<td>SKL
</td>
</tr></table>
<p>
<div>
<pre>Pstore had the latest GPF information saved. I copied it out and then ran
# rm /sys/fs/pstore/*
Below is dump what happened
Kernel version c1374a7a4a7fb0093d98ad6aa7071c8671fcdf08
from <a href="https://cgit.freedesktop.org/drm-tip">https://cgit.freedesktop.org/drm-tip</a>
Kernel configuration
<a href="https://intel-gfx-ci.01.org/CI/CI_DRM_2352/kernel.config.bz2">https://intel-gfx-ci.01.org/CI/CI_DRM_2352/kernel.config.bz2</a>
Tomi
[ 605.374955] ======================================================
[ 605.381281] [ INFO: possible circular locking dependency detected ]
[ 605.387679] 4.11.0-rc2-CI-CI_DRM_2352+ #1 Not tainted
[ 605.392826] -------------------------------------------------------
[ 605.399196] rm/7298 is trying to acquire lock:
[ 605.403720] (&psinfo->read_mutex){+.+.+.}, at: [<ffffffff813e183f>]
pstore_unlink+0x3f/0xa0
[ 605.412300]
[ 605.412300] but task is already holding lock:
[ 605.418237] (&sb->s_type->i_mutex_key#14){++++++}, at: [<ffffffff812157ec>]
vfs_unlink+0x4c/0x19
0
[ 605.427397]
[ 605.427397] which lock already depends on the new lock.
[ 605.427397]
[ 605.435770]
[ 605.435770] the existing dependency chain (in reverse order) is:
[ 605.443396]
[ 605.443396] -> #1 (&sb->s_type->i_mutex_key#14){++++++}:
[ 605.450347] lock_acquire+0xc9/0x220
[ 605.454551] down_write+0x3f/0x70
[ 605.458484] pstore_mkfile+0x1f4/0x460
[ 605.462835] pstore_get_records+0x17a/0x320
[ 605.467664] pstore_fill_super+0xa4/0xc0
[ 605.472205] mount_single+0x89/0xb0
[ 605.476314] pstore_mount+0x13/0x20
[ 605.480411] mount_fs+0xf/0x90
[ 605.484122] vfs_kern_mount+0x66/0x170
[ 605.488464] do_mount+0x190/0xd50
[ 605.492397] SyS_mount+0x90/0xd0
[ 605.496212] entry_SYSCALL_64_fastpath+0x1c/0xb1
[ 605.501496]
[ 605.501496] -> #0 (&psinfo->read_mutex){+.+.+.}:
[ 605.507747] __lock_acquire+0x1ac0/0x1bb0
[ 605.512401] lock_acquire+0xc9/0x220
[ 605.516594] __mutex_lock+0x6e/0x990
[ 605.520755] mutex_lock_nested+0x16/0x20
[ 605.525279] pstore_unlink+0x3f/0xa0
[ 605.529465] vfs_unlink+0xb5/0x190
[ 605.533477] do_unlinkat+0x24c/0x2a0
[ 605.537672] SyS_unlinkat+0x16/0x30
[ 605.541781] entry_SYSCALL_64_fastpath+0x1c/0xb1
[ 605.547067]
[ 605.547067] other info that might help us debug this:
[ 605.547067]
[ 605.555221] Possible unsafe locking scenario:
[ 605.555221]
[ 605.561280] CPU0 CPU1
[ 605.565883] ---- ----
[ 605.570502] lock(&sb->s_type->i_mutex_key#14);
[ 605.575217] lock(&psinfo->read_mutex);
[ 605.581803]
lock(&sb->s_type->i_mutex_key#14);
[ 605.589159] lock(&psinfo->read_mutex);
[ 605.593156]
[ 605.593156] *** DEADLOCK ***
[ 605.593156]
[ 605.599214] 3 locks held by rm/7298:
[ 605.602896] #0: (sb_writers#11){.+.+..}, at: [<ffffffff8122e85f>]
mnt_want_write+0x1f/0x50
[ 605.611490] #1: (&sb->s_type->i_mutex_key#14/1){+.+...}, at:
[<ffffffff8121a7dc>] do_unlinkat+0
x11c/0x2a0
[ 605.621417] #2: (&sb->s_type->i_mutex_key#14){++++++}, at:
[<ffffffff812157ec>] vfs_unlink+0x4c
/0x190
[ 605.630995]
[ 605.630995] stack backtrace:
[ 605.635450] CPU: 7 PID: 7298 Comm: rm Not tainted 4.11.0-rc2-CI-CI_DRM_2352+
#1
[ 605.642999] Hardware name: Gigabyte Technology Co., Ltd.
Z170X-UD5/Z170X-UD5-CF, BIOS F21 01/06/2
017
[ 605.652305] Call Trace:
[ 605.654814] dump_stack+0x67/0x92
[ 605.658184] print_circular_bug+0x1e0/0x2e0
[ 605.662465] __lock_acquire+0x1ac0/0x1bb0
[ 605.666634] ? retint_kernel+0x2d/0x2d
[ 605.670456] lock_acquire+0xc9/0x220
[ 605.674112] ? pstore_unlink+0x3f/0xa0
[ 605.677970] ? pstore_unlink+0x3f/0xa0
[ 605.681818] __mutex_lock+0x6e/0x990
[ 605.685456] ? pstore_unlink+0x3f/0xa0
[ 605.689791] ? pstore_unlink+0x3f/0xa0
[ 605.694124] ? vfs_unlink+0x4c/0x190
[ 605.698310] mutex_lock_nested+0x16/0x20
[ 605.702859] pstore_unlink+0x3f/0xa0
[ 605.707021] vfs_unlink+0xb5/0x190
[ 605.711024] do_unlinkat+0x24c/0x2a0
[ 605.715194] SyS_unlinkat+0x16/0x30
[ 605.719275] entry_SYSCALL_64_fastpath+0x1c/0xb1
[ 605.724543] RIP: 0033:0x7f8b08073ed7
[ 605.728676] RSP: 002b:00007ffe70eff628 EFLAGS: 00000206 ORIG_RAX:
0000000000000107
[ 605.736929] RAX: ffffffffffffffda RBX: ffffffff8147ea93 RCX:
00007f8b08073ed7
[ 605.744711] RDX: 0000000000000000 RSI: 0000000001450000 RDI:
00000000ffffff9c
[ 605.752512] RBP: ffffc9000338ff88 R08: 0000000000000003 R09:
0000000000000000
[ 605.760276] R10: 000000000000015e R11: 0000000000000206 R12:
0000000000000000
[ 605.768040] R13: 00007ffe70eff750 R14: 000000000144ff70 R15:
0000000001451230
[ 605.775800] ? __this_cpu_preempt_check+0x13/0x20</pre>
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