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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Lyude Paul <lyude@redhat.com>,
	Karol Herbst <kherbst@redhat.com>,
	Ben Skeggs <bskeggs@redhat.com>
Subject: [PATCH 4.16 46/72] drm/nouveau: Fix deadlock in nv50_mstm_register_connector()
Date: Mon, 14 May 2018 08:49:03 +0200	[thread overview]
Message-ID: <20180514064825.155592631@linuxfoundation.org> (raw)
In-Reply-To: <20180514064823.033169170@linuxfoundation.org>

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Lyude Paul <lyude@redhat.com>

commit 352672db857290ab5b0e2b6a99c414f92bee024c upstream.

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 (&helper->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:

-> #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

-> #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

-> #1 (&dev->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

-> #0 (&helper->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:
  &helper->lock --> crtc_ww_class_acquire --> 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(&helper->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)(&mgr->work)){+.+.}, at: process_one_work+0x187/0x650
 #2: 00000000586ca0df (&dev->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 <lyude@redhat.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/nouveau/nv50_display.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

--- a/drivers/gpu/drm/nouveau/nv50_display.c
+++ b/drivers/gpu/drm/nouveau/nv50_display.c
@@ -3272,10 +3272,11 @@ nv50_mstm_destroy_connector(struct drm_d
 
 	drm_connector_unregister(&mstc->connector);
 
-	drm_modeset_lock_all(drm->dev);
 	drm_fb_helper_remove_one_connector(&drm->fbcon->helper, &mstc->connector);
+
+	drm_modeset_lock(&drm->dev->mode_config.connection_mutex, NULL);
 	mstc->port = NULL;
-	drm_modeset_unlock_all(drm->dev);
+	drm_modeset_unlock(&drm->dev->mode_config.connection_mutex);
 
 	drm_connector_unreference(&mstc->connector);
 }
@@ -3285,9 +3286,7 @@ nv50_mstm_register_connector(struct drm_
 {
 	struct nouveau_drm *drm = nouveau_drm(connector->dev);
 
-	drm_modeset_lock_all(drm->dev);
 	drm_fb_helper_add_one_connector(&drm->fbcon->helper, connector);
-	drm_modeset_unlock_all(drm->dev);
 
 	drm_connector_register(connector);
 }

  parent reply	other threads:[~2018-05-14  6:49 UTC|newest]

Thread overview: 86+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-14  6:48 [PATCH 4.16 00/72] 4.16.9-stable review Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 01/72] ipvs: fix rtnl_lock lockups caused by start_sync_thread Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 02/72] netfilter: ebtables: dont attempt to allocate 0-sized compat array Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 03/72] clk: ti: fix flag space conflict with clkctrl clocks Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 04/72] kcm: Call strp_stop before strp_done in kcm_attach Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 05/72] rds: tcp: must use spin_lock_irq* and not spin_lock_bh with rds_tcp_conn_lock Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 06/72] crypto: af_alg - fix possible uninit-value in alg_bind() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 07/72] netlink: fix uninit-value in netlink_sendmsg Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 08/72] net: fix rtnh_ok() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 09/72] net: initialize skb->peeked when cloning Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 10/72] net: fix uninit-value in __hw_addr_add_ex() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 11/72] dccp: initialize ireq->ir_mark Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 12/72] ipv4: fix uninit-value in ip_route_output_key_hash_rcu() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 13/72] soreuseport: initialise timewait reuseport field Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 14/72] inetpeer: fix uninit-value in inet_getpeer Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 15/72] bpf/tracing: fix a deadlock in perf_event_detach_bpf_prog Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 16/72] memcg: fix per_node_info cleanup Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 17/72] perf: Remove superfluous allocation error check Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 18/72] i2c: dev: prevent ZERO_SIZE_PTR deref in i2cdev_ioctl_rdwr() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 19/72] tcp: fix TCP_REPAIR_QUEUE bound checking Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 20/72] bdi: wake up concurrent wb_shutdown() callers Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 21/72] bdi: Fix use after free bug in debugfs_remove() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 22/72] bdi: Fix oops in wb_workfn() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 23/72] compat: fix 4-byte infoleak via uninitialized struct field Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 24/72] gpioib: do not free unrequested descriptors Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 25/72] gpio: fix aspeed_gpio unmask irq Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 26/72] gpio: fix error path in lineevent_create Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 27/72] rfkill: gpio: fix memory leak in probe error path Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 28/72] libata: Apply NOLPM quirk for SanDisk SD7UB3Q*G1001 SSDs Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 29/72] dm integrity: use kvfree for kvmallocd memory Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 30/72] tracing: Fix regex_match_front() to not over compare the test string Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 31/72] z3fold: fix reclaim lock-ups Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 32/72] mm: sections are not offlined during memory hotremove Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 33/72] mm, oom: fix concurrent munlock and oom reaper unmap, v3 Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 34/72] ceph: fix rsize/wsize capping in ceph_direct_read_write() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 35/72] can: flexcan: fix endianess detection Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 36/72] can: kvaser_usb: Increase correct stats counter in kvaser_usb_rx_can_msg() Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 37/72] can: hi311x: Acquire SPI lock on ->do_get_berr_counter Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 38/72] can: hi311x: Work around TX complete interrupt erratum Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 39/72] mtd: rawnand: marvell: pass ms delay to wait_op Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 40/72] mtd: rawnand: marvell: fix command xtype in BCH write hook Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 41/72] mtd: rawnand: Make sure we wait tWB before polling the STATUS reg Greg Kroah-Hartman
2018-05-14  7:32   ` Geert Uytterhoeven
2018-05-14  9:04     ` Greg Kroah-Hartman
2018-05-14  9:09       ` Boris Brezillon
2018-05-14 10:54         ` Geert Uytterhoeven
2018-05-14  9:32       ` Geert Uytterhoeven
2018-05-14 16:50       ` Greg Kroah-Hartman
2018-05-14  6:48 ` [PATCH 4.16 42/72] drm/vc4: Fix scaling of uni-planar formats Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 43/72] drm/ttm: Use GFP_TRANSHUGE_LIGHT for allocating huge pages Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 44/72] drm/i915: Fix drm:intel_enable_lvds ERROR message in kernel log Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 45/72] drm/i915: Adjust eDPs logical vco in a reliable place Greg Kroah-Hartman
2018-05-14  6:49 ` Greg Kroah-Hartman [this message]
2018-05-14  6:49 ` [PATCH 4.16 47/72] drm/nouveau/ttm: dont dereference nvbo::cli, it can outlive client Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 48/72] drm/atomic: Clean old_state/new_state in drm_atomic_state_default_clear() Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 49/72] drm/atomic: Clean private obj " Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 50/72] net: atm: Fix potential Spectre v1 Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 51/72] atm: zatm: " Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 52/72] PCI / PM: Always check PME wakeup capability for runtime wakeup support Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 53/72] PCI / PM: Check device_may_wakeup() in pci_enable_wake() Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 54/72] cpufreq: schedutil: Avoid using invalid next_freq Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 55/72] arm: dts: imx[35]*: declare flexcan devices to be compatible to imx25s flexcan Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 56/72] Revert "Bluetooth: btusb: Fix quirk for Atheros 1525/QCA6174" Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 57/72] Bluetooth: btusb: Add Dell XPS 13 9360 to btusb_needs_reset_resume_table Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 58/72] Bluetooth: btusb: Only check needs_reset_resume DMI table for QCA rome chipsets Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 59/72] thermal: exynos: Reading temperature makes sense only when TMU is turned on Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 60/72] thermal: exynos: Propagate error value from tmu_read() Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 61/72] nvme: add quirk to force medium priority for SQ creation Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 62/72] nvme: Fix sync controller reset return Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 63/72] smb3: directory sync should not return an error Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 64/72] swiotlb: silent unwanted warning "buffer is full" Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 65/72] sched/core: Fix possible Spectre-v1 indexing for sched_prio_to_weight[] Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 66/72] sched/autogroup: " Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 67/72] tracing/uprobe_event: Fix strncpy corner case Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 68/72] perf/x86: Fix possible Spectre-v1 indexing for hw_perf_event cache_* Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 69/72] perf/x86/cstate: Fix possible Spectre-v1 indexing for pkg_msr Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 70/72] perf/x86/msr: Fix possible Spectre-v1 indexing in the MSR driver Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 71/72] perf/core: Fix possible Spectre-v1 indexing for ->aux_pages[] Greg Kroah-Hartman
2018-05-14  6:49 ` [PATCH 4.16 72/72] perf/x86: Fix possible Spectre-v1 indexing for x86_pmu::event_map() Greg Kroah-Hartman
2018-05-14 13:45 ` [PATCH 4.16 00/72] 4.16.9-stable review kernelci.org bot
2018-05-14 16:27 ` Guenter Roeck
2018-05-14 16:51   ` Greg Kroah-Hartman
2018-05-14 22:01 ` Shuah Khan
2018-05-15  6:47   ` Greg Kroah-Hartman
2018-05-15  5:31 ` Naresh Kamboju
2018-05-15  6:47   ` Greg Kroah-Hartman

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