<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/drivers/gpu/drm/nouveau, branch linux-4.17.y</title>
<subtitle>Hosts the 0x221E linux distro kernel.</subtitle>
<id>https://universe.0xinfinity.dev/distro/kernel/atom?h=linux-4.17.y</id>
<link rel='self' href='https://universe.0xinfinity.dev/distro/kernel/atom?h=linux-4.17.y'/>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/'/>
<updated>2018-08-24T11:07:10Z</updated>
<entry>
<title>drm/nouveau/gem: off by one bugs in nouveau_gem_pushbuf_reloc_apply()</title>
<updated>2018-08-24T11:07:10Z</updated>
<author>
<name>Dan Carpenter</name>
<email>dan.carpenter@oracle.com</email>
</author>
<published>2018-07-03T12:30:56Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=926fb5fe74d20370657c446f0fccb9b6bc7ea49c'/>
<id>urn:sha1:926fb5fe74d20370657c446f0fccb9b6bc7ea49c</id>
<content type='text'>
[ Upstream commit 7f073d011f93e92d4d225526b9ab6b8b0bbd6613 ]

The bo array has req-&gt;nr_buffers elements so the &gt; should be &gt;= so we
don't read beyond the end of the array.

Fixes: a1606a9596e5 ("drm/nouveau: new gem pushbuf interface, bump to 0.0.16")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>drm/nouveau/fifo/gk104-: poll for runlist update completion</title>
<updated>2018-08-03T05:47:48Z</updated>
<author>
<name>Ben Skeggs</name>
<email>bskeggs@redhat.com</email>
</author>
<published>2018-05-08T10:39:46Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=8867977862123c4c684dfa118ae6633518afe9ff'/>
<id>urn:sha1:8867977862123c4c684dfa118ae6633518afe9ff</id>
<content type='text'>
[ Upstream commit 4f2fc25c0f8bcc8db1b8a7b21e88c3d7f35c5acb ]

Newer HW doesn't appear to send this event, which will cause long delays
in runlist updates if they don't complete immediately.

RM doesn't use these events anywhere, and an NVGPU commit message notes
that polling is the preferred method even on HW that supports the event.

Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>drm/nouveau/gem: lookup VMAs for buffers referenced by pushbuf ioctl</title>
<updated>2018-08-03T05:47:48Z</updated>
<author>
<name>Ben Skeggs</name>
<email>bskeggs@redhat.com</email>
</author>
<published>2018-05-08T10:39:47Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=bcc16811023394a5e61a20c107f1fa560a28b7c1'/>
<id>urn:sha1:bcc16811023394a5e61a20c107f1fa560a28b7c1</id>
<content type='text'>
[ Upstream commit 19ca10d82e33bcfe92412c461fc3534ec1e14747 ]

We previously only did this for push buffers, but an upcoming patch will
need to attach fences to all VMAs to resolve another issue.

Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>drm/nouveau: remove fence wait code from deferred client work handler</title>
<updated>2018-08-03T05:47:48Z</updated>
<author>
<name>Ben Skeggs</name>
<email>bskeggs@redhat.com</email>
</author>
<published>2018-05-08T10:39:47Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=125efb51cdd9c7e8649add5bc3866e3ed325ff76'/>
<id>urn:sha1:125efb51cdd9c7e8649add5bc3866e3ed325ff76</id>
<content type='text'>
[ Upstream commit 11e451e74050d9e9030581ce40337838acfcea5b ]

Fences attached to deferred client work items now originate from channels
belonging to the client, meaning we can be certain they've been signalled
before we destroy a client.

This closes a race that could happen if the dma_fence_wait_timeout() call
didn't succeed.  When the fence was later signalled, a use-after-free was
possible.

Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>drm/nouveau: Set DRIVER_ATOMIC cap earlier to fix debugfs</title>
<updated>2018-07-28T05:57:13Z</updated>
<author>
<name>Lyude Paul</name>
<email>lyude@redhat.com</email>
</author>
<published>2018-07-03T20:31:41Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=15f08f48ac61604339788b57cfa0e002c3d64714'/>
<id>urn:sha1:15f08f48ac61604339788b57cfa0e002c3d64714</id>
<content type='text'>
commit eb493fbc150f4a28151ae1ee84f24395989f3600 upstream.

Currently nouveau doesn't actually expose the state debugfs file that's
usually provided for any modesetting driver that supports atomic, even
if nouveau is loaded with atomic=1. This is due to the fact that the
standard debugfs files that DRM creates for atomic drivers is called
when drm_get_pci_dev() is called from nouveau_drm.c. This happens well
before we've initialized the display core, which is currently
responsible for setting the DRIVER_ATOMIC cap.

So, move the atomic option into nouveau_drm.c and just add the
DRIVER_ATOMIC cap whenever it's enabled on the kernel commandline. This
shouldn't cause any actual issues, as the atomic ioctl will still fail
as expected even if the display core doesn't disable it until later in
the init sequence. This also provides the added benefit of being able to
use the state debugfs file to check the current display state even if
clients aren't allowed to modify it through anything other than the
legacy ioctls.

Additionally, disable the DRIVER_ATOMIC cap in nv04's display core, as
this was already disabled there previously.

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>drm/nouveau/drm/nouveau: Fix runtime PM leak in nv50_disp_atomic_commit()</title>
<updated>2018-07-28T05:57:13Z</updated>
<author>
<name>Lyude Paul</name>
<email>lyude@redhat.com</email>
</author>
<published>2018-07-12T17:02:53Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=74930a2dca9a6607a169cae9ae62606109fd4d73'/>
<id>urn:sha1:74930a2dca9a6607a169cae9ae62606109fd4d73</id>
<content type='text'>
commit e5d54f1935722f83df7619f3978f774c2b802cd8 upstream.

A CRTC being enabled doesn't mean it's on! It doesn't even necessarily
mean it's being used. This fixes runtime PM leaks on the P50 I've got
next to me.

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;


</content>
</entry>
<entry>
<title>drm/nouveau: Avoid looping through fake MST connectors</title>
<updated>2018-07-25T09:26:10Z</updated>
<author>
<name>Lyude Paul</name>
<email>lyude@redhat.com</email>
</author>
<published>2018-07-13T17:06:33Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=44c7b7c90d1dabb975bbf9780016e6fca192a973'/>
<id>urn:sha1:44c7b7c90d1dabb975bbf9780016e6fca192a973</id>
<content type='text'>
commit 37afe55b4ae0600deafe7c0e0e658593c4754f1b upstream.

When MST and atomic were introduced to nouveau, another structure that
could contain a drm_connector embedded within it was introduced; struct
nv50_mstc. This meant that we no longer would be able to simply loop
through our connector list and assume that nouveau_connector() would
return a proper pointer for each connector, since the assertion that
all connectors coming from nouveau have a full nouveau_connector struct
became invalid.

Unfortunately, none of the actual code that looped through connectors
ever got updated, which means that we've been causing invalid memory
accesses for quite a while now.

An example that was caught by KASAN:

[  201.038698] ==================================================================
[  201.038792] BUG: KASAN: slab-out-of-bounds in nvif_notify_get+0x190/0x1a0 [nouveau]
[  201.038797] Read of size 4 at addr ffff88076738c650 by task kworker/0:3/718
[  201.038800]
[  201.038822] CPU: 0 PID: 718 Comm: kworker/0:3 Tainted: G           O      4.18.0-rc4Lyude-Test+ #1
[  201.038825] Hardware name: LENOVO 20EQS64N0B/20EQS64N0B, BIOS N1EET78W (1.51 ) 05/18/2018
[  201.038882] Workqueue: events nouveau_display_hpd_work [nouveau]
[  201.038887] Call Trace:
[  201.038894]  dump_stack+0xa4/0xfd
[  201.038900]  print_address_description+0x71/0x239
[  201.038929]  ? nvif_notify_get+0x190/0x1a0 [nouveau]
[  201.038935]  kasan_report.cold.6+0x242/0x2fe
[  201.038942]  __asan_report_load4_noabort+0x19/0x20
[  201.038970]  nvif_notify_get+0x190/0x1a0 [nouveau]
[  201.038998]  ? nvif_notify_put+0x1f0/0x1f0 [nouveau]
[  201.039003]  ? kmsg_dump_rewind_nolock+0xe4/0xe4
[  201.039049]  nouveau_display_init.cold.12+0x34/0x39 [nouveau]
[  201.039089]  ? nouveau_user_framebuffer_create+0x120/0x120 [nouveau]
[  201.039133]  nouveau_display_resume+0x5c0/0x810 [nouveau]
[  201.039173]  ? nvkm_client_ioctl+0x20/0x20 [nouveau]
[  201.039215]  nouveau_do_resume+0x19f/0x570 [nouveau]
[  201.039256]  nouveau_pmops_runtime_resume+0xd8/0x2a0 [nouveau]
[  201.039264]  pci_pm_runtime_resume+0x130/0x250
[  201.039269]  ? pci_restore_standard_config+0x70/0x70
[  201.039275]  __rpm_callback+0x1f2/0x5d0
[  201.039279]  ? rpm_resume+0x560/0x18a0
[  201.039283]  ? pci_restore_standard_config+0x70/0x70
[  201.039287]  ? pci_restore_standard_config+0x70/0x70
[  201.039291]  ? pci_restore_standard_config+0x70/0x70
[  201.039296]  rpm_callback+0x175/0x210
[  201.039300]  ? pci_restore_standard_config+0x70/0x70
[  201.039305]  rpm_resume+0xcc3/0x18a0
[  201.039312]  ? rpm_callback+0x210/0x210
[  201.039317]  ? __pm_runtime_resume+0x9e/0x100
[  201.039322]  ? kasan_check_write+0x14/0x20
[  201.039326]  ? do_raw_spin_lock+0xc2/0x1c0
[  201.039333]  __pm_runtime_resume+0xac/0x100
[  201.039374]  nouveau_display_hpd_work+0x67/0x1f0 [nouveau]
[  201.039380]  process_one_work+0x7a0/0x14d0
[  201.039388]  ? cancel_delayed_work_sync+0x20/0x20
[  201.039392]  ? lock_acquire+0x113/0x310
[  201.039398]  ? kasan_check_write+0x14/0x20
[  201.039402]  ? do_raw_spin_lock+0xc2/0x1c0
[  201.039409]  worker_thread+0x86/0xb50
[  201.039418]  kthread+0x2e9/0x3a0
[  201.039422]  ? process_one_work+0x14d0/0x14d0
[  201.039426]  ? kthread_create_worker_on_cpu+0xc0/0xc0
[  201.039431]  ret_from_fork+0x3a/0x50
[  201.039441]
[  201.039444] Allocated by task 79:
[  201.039449]  save_stack+0x43/0xd0
[  201.039452]  kasan_kmalloc+0xc4/0xe0
[  201.039456]  kmem_cache_alloc_trace+0x10a/0x260
[  201.039494]  nv50_mstm_add_connector+0x9a/0x340 [nouveau]
[  201.039504]  drm_dp_add_port+0xff5/0x1fc0 [drm_kms_helper]
[  201.039511]  drm_dp_send_link_address+0x4a7/0x740 [drm_kms_helper]
[  201.039518]  drm_dp_check_and_send_link_address+0x1a7/0x210 [drm_kms_helper]
[  201.039525]  drm_dp_mst_link_probe_work+0x71/0xb0 [drm_kms_helper]
[  201.039529]  process_one_work+0x7a0/0x14d0
[  201.039533]  worker_thread+0x86/0xb50
[  201.039537]  kthread+0x2e9/0x3a0
[  201.039541]  ret_from_fork+0x3a/0x50
[  201.039543]
[  201.039546] Freed by task 0:
[  201.039549] (stack is not available)
[  201.039551]
[  201.039555] The buggy address belongs to the object at ffff88076738c1a8
                                 which belongs to the cache kmalloc-2048 of size 2048
[  201.039559] The buggy address is located 1192 bytes inside of
                                 2048-byte region [ffff88076738c1a8, ffff88076738c9a8)
[  201.039563] The buggy address belongs to the page:
[  201.039567] page:ffffea001d9ce200 count:1 mapcount:0 mapping:ffff88084000d0c0 index:0x0 compound_mapcount: 0
[  201.039573] flags: 0x8000000000008100(slab|head)
[  201.039578] raw: 8000000000008100 ffffea001da3be08 ffffea001da25a08 ffff88084000d0c0
[  201.039582] raw: 0000000000000000 00000000000d000d 00000001ffffffff 0000000000000000
[  201.039585] page dumped because: kasan: bad access detected
[  201.039588]
[  201.039591] Memory state around the buggy address:
[  201.039594]  ffff88076738c500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[  201.039598]  ffff88076738c580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[  201.039601] &gt;ffff88076738c600: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
[  201.039604]                                                  ^
[  201.039607]  ffff88076738c680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  201.039611]  ffff88076738c700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  201.039613] ==================================================================

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: stable@vger.kernel.org
Cc: Karol Herbst &lt;karolherbst@gmail.com&gt;
Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>drm/nouveau: Use drm_connector_list_iter_* for iterating connectors</title>
<updated>2018-07-25T09:26:09Z</updated>
<author>
<name>Lyude Paul</name>
<email>lyude@redhat.com</email>
</author>
<published>2018-07-13T17:06:32Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=c89b8c6f8dd304feb29e4f6f17efa50951f87971'/>
<id>urn:sha1:c89b8c6f8dd304feb29e4f6f17efa50951f87971</id>
<content type='text'>
commit 22b76bbe089cd901f5260ecb9a3dc41f9edb97a0 upstream.

Every codepath in nouveau that loops through the connector list
currently does so using the old method, which is prone to race
conditions from MST connectors being created and destroyed. This has
been causing a multitude of problems, including memory corruption from
trying to access connectors that have already been freed!

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: stable@vger.kernel.org
Cc: Karol Herbst &lt;karolherbst@gmail.com&gt;
Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>drm/nouveau: Remove bogus crtc check in pmops_runtime_idle</title>
<updated>2018-07-25T09:26:09Z</updated>
<author>
<name>Lyude Paul</name>
<email>lyude@redhat.com</email>
</author>
<published>2018-07-12T17:02:54Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=99701888bc061bc3b8a7c73f9911bc2c654776c9'/>
<id>urn:sha1:99701888bc061bc3b8a7c73f9911bc2c654776c9</id>
<content type='text'>
commit 68fe23a626b67b56c912c496ea43ed537ea9708f upstream.

This both uses the legacy modesetting structures in a racy manner, and
additionally also doesn't even check the right variable (enabled != the
CRTC is actually turned on for atomic).

This fixes issues on my P50 regarding the dedicated GPU not entering
runtime suspend.

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: stable@vger.kernel.org
Reviewed-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>drm/nouveau: Fix deadlock in nv50_mstm_register_connector()</title>
<updated>2018-05-10T03:11:52Z</updated>
<author>
<name>Lyude Paul</name>
<email>lyude@redhat.com</email>
</author>
<published>2018-05-02T23:38:48Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=352672db857290ab5b0e2b6a99c414f92bee024c'/>
<id>urn:sha1:352672db857290ab5b0e2b6a99c414f92bee024c</id>
<content type='text'>
Currently; we're grabbing all of the modesetting locks before adding MST
connectors to fbdev. This isn't actually necessary, and causes a
deadlock as well:

======================================================
WARNING: possible circular locking dependency detected
4.17.0-rc3Lyude-Test+ #1 Tainted: G           O
------------------------------------------------------
kworker/1:0/18 is trying to acquire lock:
00000000c832f62d (&amp;helper-&gt;lock){+.+.}, at: drm_fb_helper_add_one_connector+0x2a/0x60 [drm_kms_helper]

but task is already holding lock:
00000000942e28e2 (crtc_ww_class_mutex){+.+.}, at: drm_modeset_backoff+0x8e/0x1c0 [drm]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-&gt; #3 (crtc_ww_class_mutex){+.+.}:
       ww_mutex_lock+0x43/0x80
       drm_modeset_lock+0x71/0x130 [drm]
       drm_helper_probe_single_connector_modes+0x7d/0x6b0 [drm_kms_helper]
       drm_setup_crtcs+0x15e/0xc90 [drm_kms_helper]
       __drm_fb_helper_initial_config_and_unlock+0x29/0x480 [drm_kms_helper]
       nouveau_fbcon_init+0x138/0x1a0 [nouveau]
       nouveau_drm_load+0x173/0x7e0 [nouveau]
       drm_dev_register+0x134/0x1c0 [drm]
       drm_get_pci_dev+0x8e/0x160 [drm]
       nouveau_drm_probe+0x1a9/0x230 [nouveau]
       pci_device_probe+0xcd/0x150
       driver_probe_device+0x30b/0x480
       __driver_attach+0xbc/0xe0
       bus_for_each_dev+0x67/0x90
       bus_add_driver+0x164/0x260
       driver_register+0x57/0xc0
       do_one_initcall+0x4d/0x323
       do_init_module+0x5b/0x1f8
       load_module+0x20e5/0x2ac0
       __do_sys_finit_module+0xb7/0xd0
       do_syscall_64+0x60/0x1b0
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-&gt; #2 (crtc_ww_class_acquire){+.+.}:
       drm_helper_probe_single_connector_modes+0x58/0x6b0 [drm_kms_helper]
       drm_setup_crtcs+0x15e/0xc90 [drm_kms_helper]
       __drm_fb_helper_initial_config_and_unlock+0x29/0x480 [drm_kms_helper]
       nouveau_fbcon_init+0x138/0x1a0 [nouveau]
       nouveau_drm_load+0x173/0x7e0 [nouveau]
       drm_dev_register+0x134/0x1c0 [drm]
       drm_get_pci_dev+0x8e/0x160 [drm]
       nouveau_drm_probe+0x1a9/0x230 [nouveau]
       pci_device_probe+0xcd/0x150
       driver_probe_device+0x30b/0x480
       __driver_attach+0xbc/0xe0
       bus_for_each_dev+0x67/0x90
       bus_add_driver+0x164/0x260
       driver_register+0x57/0xc0
       do_one_initcall+0x4d/0x323
       do_init_module+0x5b/0x1f8
       load_module+0x20e5/0x2ac0
       __do_sys_finit_module+0xb7/0xd0
       do_syscall_64+0x60/0x1b0
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-&gt; #1 (&amp;dev-&gt;mode_config.mutex){+.+.}:
       drm_setup_crtcs+0x10c/0xc90 [drm_kms_helper]
       __drm_fb_helper_initial_config_and_unlock+0x29/0x480 [drm_kms_helper]
       nouveau_fbcon_init+0x138/0x1a0 [nouveau]
       nouveau_drm_load+0x173/0x7e0 [nouveau]
       drm_dev_register+0x134/0x1c0 [drm]
       drm_get_pci_dev+0x8e/0x160 [drm]
       nouveau_drm_probe+0x1a9/0x230 [nouveau]
       pci_device_probe+0xcd/0x150
       driver_probe_device+0x30b/0x480
       __driver_attach+0xbc/0xe0
       bus_for_each_dev+0x67/0x90
       bus_add_driver+0x164/0x260
       driver_register+0x57/0xc0
       do_one_initcall+0x4d/0x323
       do_init_module+0x5b/0x1f8
       load_module+0x20e5/0x2ac0
       __do_sys_finit_module+0xb7/0xd0
       do_syscall_64+0x60/0x1b0
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-&gt; #0 (&amp;helper-&gt;lock){+.+.}:
       __mutex_lock+0x70/0x9d0
       drm_fb_helper_add_one_connector+0x2a/0x60 [drm_kms_helper]
       nv50_mstm_register_connector+0x2c/0x50 [nouveau]
       drm_dp_add_port+0x2f5/0x420 [drm_kms_helper]
       drm_dp_send_link_address+0x155/0x1e0 [drm_kms_helper]
       drm_dp_add_port+0x33f/0x420 [drm_kms_helper]
       drm_dp_send_link_address+0x155/0x1e0 [drm_kms_helper]
       drm_dp_check_and_send_link_address+0x87/0xd0 [drm_kms_helper]
       drm_dp_mst_link_probe_work+0x4d/0x80 [drm_kms_helper]
       process_one_work+0x20d/0x650
       worker_thread+0x3a/0x390
       kthread+0x11e/0x140
       ret_from_fork+0x3a/0x50

other info that might help us debug this:
Chain exists of:
  &amp;helper-&gt;lock --&gt; crtc_ww_class_acquire --&gt; crtc_ww_class_mutex
 Possible unsafe locking scenario:
       CPU0                    CPU1
       ----                    ----
  lock(crtc_ww_class_mutex);
                               lock(crtc_ww_class_acquire);
                               lock(crtc_ww_class_mutex);
  lock(&amp;helper-&gt;lock);

 *** DEADLOCK ***
5 locks held by kworker/1:0/18:
 #0: 000000004a05cd50 ((wq_completion)"events_long"){+.+.}, at: process_one_work+0x187/0x650
 #1: 00000000601c11d1 ((work_completion)(&amp;mgr-&gt;work)){+.+.}, at: process_one_work+0x187/0x650
 #2: 00000000586ca0df (&amp;dev-&gt;mode_config.mutex){+.+.}, at: drm_modeset_lock_all+0x3a/0x1b0 [drm]
 #3: 00000000d3ca0ffa (crtc_ww_class_acquire){+.+.}, at: drm_modeset_lock_all+0x44/0x1b0 [drm]
 #4: 00000000942e28e2 (crtc_ww_class_mutex){+.+.}, at: drm_modeset_backoff+0x8e/0x1c0 [drm]

stack backtrace:
CPU: 1 PID: 18 Comm: kworker/1:0 Tainted: G           O      4.17.0-rc3Lyude-Test+ #1
Hardware name: Gateway FX6840/FX6840, BIOS P01-A3         05/17/2010
Workqueue: events_long drm_dp_mst_link_probe_work [drm_kms_helper]
Call Trace:
 dump_stack+0x85/0xcb
 print_circular_bug.isra.38+0x1ce/0x1db
 __lock_acquire+0x128f/0x1350
 ? lock_acquire+0x9f/0x200
 ? lock_acquire+0x9f/0x200
 ? __ww_mutex_lock.constprop.13+0x8f/0x1000
 lock_acquire+0x9f/0x200
 ? drm_fb_helper_add_one_connector+0x2a/0x60 [drm_kms_helper]
 ? drm_fb_helper_add_one_connector+0x2a/0x60 [drm_kms_helper]
 __mutex_lock+0x70/0x9d0
 ? drm_fb_helper_add_one_connector+0x2a/0x60 [drm_kms_helper]
 ? ww_mutex_lock+0x43/0x80
 ? _cond_resched+0x15/0x30
 ? ww_mutex_lock+0x43/0x80
 ? drm_modeset_lock+0xb2/0x130 [drm]
 ? drm_fb_helper_add_one_connector+0x2a/0x60 [drm_kms_helper]
 drm_fb_helper_add_one_connector+0x2a/0x60 [drm_kms_helper]
 nv50_mstm_register_connector+0x2c/0x50 [nouveau]
 drm_dp_add_port+0x2f5/0x420 [drm_kms_helper]
 ? mark_held_locks+0x50/0x80
 ? kfree+0xcf/0x2a0
 ? drm_dp_check_mstb_guid+0xd6/0x120 [drm_kms_helper]
 ? trace_hardirqs_on_caller+0xed/0x180
 ? drm_dp_check_mstb_guid+0xd6/0x120 [drm_kms_helper]
 drm_dp_send_link_address+0x155/0x1e0 [drm_kms_helper]
 drm_dp_add_port+0x33f/0x420 [drm_kms_helper]
 ? nouveau_connector_aux_xfer+0x7c/0xb0 [nouveau]
 ? find_held_lock+0x2d/0x90
 ? drm_dp_dpcd_access+0xd9/0xf0 [drm_kms_helper]
 ? __mutex_unlock_slowpath+0x3b/0x280
 ? drm_dp_dpcd_access+0xd9/0xf0 [drm_kms_helper]
 drm_dp_send_link_address+0x155/0x1e0 [drm_kms_helper]
 drm_dp_check_and_send_link_address+0x87/0xd0 [drm_kms_helper]
 drm_dp_mst_link_probe_work+0x4d/0x80 [drm_kms_helper]
 process_one_work+0x20d/0x650
 worker_thread+0x3a/0x390
 ? process_one_work+0x650/0x650
 kthread+0x11e/0x140
 ? kthread_create_worker_on_cpu+0x50/0x50
 ret_from_fork+0x3a/0x50

Taking example from i915, the only time we need to hold any modesetting
locks is when changing the port on the mstc, and in that case we only
need to hold the connection mutex.

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Cc: Karol Herbst &lt;kherbst@redhat.com&gt;
Cc: stable@vger.kernel.org

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;

Signed-off-by: Ben Skeggs &lt;bskeggs@redhat.com&gt;
</content>
</entry>
</feed>
