Hi Stephen,
On 09/11/17 06:17, Stephen Hemminger wrote:
Running kernel with lockdep on my XPS13 logs a locking error from the DMAR
subsystem.
[ 32.823763] ACPI: button: The lid device is not compliant to SW_LID.
[ 32.844606] pci 0000:01:00.0: [8086:1576] type 01 class 0x060400
[ 32.844683] pci 0000:01:00.0: enabling Extended Tags
[ 32.844828] pci 0000:01:00.0: supports D1 D2
[ 32.844830] pci 0000:01:00.0: PME# supported from D0 D1 D2 D3hot D3cold
[ 32.845168] ======================================================
[ 32.845169] WARNING: possible circular locking dependency detected
[ 32.845171] 4.14.0-rc7-net-next+ #9 Not tainted
[ 32.845172] ------------------------------------------------------
[ 32.845173] kworker/u8:2/99 is trying to acquire lock:
[ 32.845174] (dmar_global_lock){++++}, at: [<ffffffff8c04297e>]
dmar_pci_bus_notifier+0x4e/0xe0
[ 32.845180]
but task is already holding lock:
[ 32.845181] (&(&priv->bus_notifier)->rwsem){++++}, at: [<ffffffff8bac35b5>]
__blocking_notifier_call_chain+0x35/0x70
[ 32.845185]
which lock already depends on the new lock.
This looks a lot like what Jan reported recently:
https://www.mail-archive.com/[email protected]/msg20151.html
Does the patch from that thread (commit ec154bf56b27 in the current
linux-next tree) work for you?
Robin.
[ 32.845186]
the existing dependency chain (in reverse order) is:
[ 32.845187]
-> #1 (&(&priv->bus_notifier)->rwsem){++++}:
[ 32.845192] lock_acquire+0xe3/0x1d0
[ 32.845194] down_write+0x40/0x70
[ 32.845196] blocking_notifier_chain_register+0x21/0xb0
[ 32.845197] bus_register_notifier+0x1c/0x20
[ 32.845199] dmar_dev_scope_init+0x2d6/0x2ff
[ 32.845200] intel_iommu_init+0x108/0x1377
[ 32.845202] pci_iommu_init+0x17/0x41
[ 32.845203] do_one_initcall+0x52/0x198
[ 32.845206] kernel_init_freeable+0x200/0x29c
[ 32.845208] kernel_init+0xe/0x100
[ 32.845209] ret_from_fork+0x2a/0x40
[ 32.845210]
-> #0 (dmar_global_lock){++++}:
[ 32.845214] __lock_acquire+0x13c9/0x1400
[ 32.845215] lock_acquire+0xe3/0x1d0
[ 32.845217] down_write+0x40/0x70
[ 32.845218] dmar_pci_bus_notifier+0x4e/0xe0
[ 32.845220] notifier_call_chain+0x4a/0x70
[ 32.845221] __blocking_notifier_call_chain+0x4d/0x70
[ 32.845222] blocking_notifier_call_chain+0x16/0x20
[ 32.845223] device_add+0x370/0x650
[ 32.845226] pci_device_add+0x1b0/0x230
[ 32.845227] pci_scan_single_device+0xb3/0xd0
[ 32.845229] pci_scan_slot+0x52/0x110
[ 32.845231] acpiphp_rescan_slot+0x7f/0x90
[ 32.845233] enable_slot+0x41/0x310
[ 32.845235] acpiphp_check_bridge.part.7+0x102/0x150
[ 32.845237] acpiphp_hotplug_notify+0x14a/0x1e0
[ 32.845238] acpi_device_hotplug+0xa1/0x4c0
[ 32.845240] acpi_hotplug_work_fn+0x1e/0x30
[ 32.845242] process_one_work+0x26c/0x680
[ 32.845243] worker_thread+0x4b/0x410
[ 32.845244] kthread+0x114/0x150
[ 32.845246] ret_from_fork+0x2a/0x40
[ 32.845247]
other info that might help us debug this:
[ 32.845248] Possible unsafe locking scenario:
[ 32.845249] CPU0 CPU1
[ 32.845250] ---- ----
[ 32.845250] lock(&(&priv->bus_notifier)->rwsem);
[ 32.845252] lock(dmar_global_lock);
[ 32.845253]
lock(&(&priv->bus_notifier)->rwsem);
[ 32.845254] lock(dmar_global_lock);
[ 32.845256]
*** DEADLOCK ***
[ 32.845258] 6 locks held by kworker/u8:2/99:
[ 32.845258] #0: ("kacpi_hotplug"){+.+.}, at: [<ffffffff8baba3a6>]
process_one_work+0x1f6/0x680
[ 32.845261] #1: ((&hpw->work)){+.+.}, at: [<ffffffff8baba3a6>]
process_one_work+0x1f6/0x680
[ 32.845264] #2: (device_hotplug_lock){+.+.}, at: [<ffffffff8c054a07>]
lock_device_hotplug+0x17/0x20
[ 32.845267] #3: (acpi_scan_lock){+.+.}, at: [<ffffffff8bf85b5c>]
acpi_device_hotplug+0x3c/0x4c0
[ 32.845269] #4: (pci_rescan_remove_lock){+.+.}, at: [<ffffffff8bf2d667>]
pci_lock_rescan_remove+0x17/0x20
[ 32.845272] #5: (&(&priv->bus_notifier)->rwsem){++++}, at:
[<ffffffff8bac35b5>] __blocking_notifier_call_chain+0x35/0x70
[ 32.845275]
stack backtrace:
[ 32.845278] CPU: 2 PID: 99 Comm: kworker/u8:2 Not tainted
4.14.0-rc7-net-next+ #9
[ 32.845278] Hardware name: Dell Inc. XPS 13 9360/05JK94, BIOS 1.3.2
01/18/2017
[ 32.845282] Workqueue: kacpi_hotplug acpi_hotplug_work_fn
[ 32.845283] Call Trace:
[ 32.845287] dump_stack+0x86/0xcf
[ 32.845289] print_circular_bug.isra.42+0x1e7/0x1f5
[ 32.845292] __lock_acquire+0x13c9/0x1400
[ 32.845294] ? __lock_acquire+0xd31/0x1400
[ 32.845296] lock_acquire+0xe3/0x1d0
[ 32.845298] ? lock_acquire+0xe3/0x1d0
[ 32.845300] ? dmar_pci_bus_notifier+0x4e/0xe0
[ 32.845302] down_write+0x40/0x70
[ 32.845303] ? dmar_pci_bus_notifier+0x4e/0xe0
[ 32.845305] dmar_pci_bus_notifier+0x4e/0xe0
[ 32.845306] notifier_call_chain+0x4a/0x70
[ 32.845308] __blocking_notifier_call_chain+0x4d/0x70
[ 32.845310] blocking_notifier_call_chain+0x16/0x20
[ 32.845311] device_add+0x370/0x650
[ 32.845313] pci_device_add+0x1b0/0x230
[ 32.845315] pci_scan_single_device+0xb3/0xd0
[ 32.845317] pci_scan_slot+0x52/0x110
[ 32.845319] acpiphp_rescan_slot+0x7f/0x90
[ 32.845321] enable_slot+0x41/0x310
[ 32.845324] ? pci_read+0x2c/0x30
[ 32.845326] ? pci_bus_read_config_dword+0x5a/0x70
[ 32.845328] ? get_slot_status+0xa3/0xe0
[ 32.845330] acpiphp_check_bridge.part.7+0x102/0x150
[ 32.845332] acpiphp_hotplug_notify+0x14a/0x1e0
[ 32.845334] ? free_bridge+0x120/0x120
[ 32.845335] acpi_device_hotplug+0xa1/0x4c0
[ 32.845337] acpi_hotplug_work_fn+0x1e/0x30
[ 32.845339] process_one_work+0x26c/0x680
[ 32.845341] worker_thread+0x4b/0x410
[ 32.845343] kthread+0x114/0x150
[ 32.845344] ? process_one_work+0x680/0x680
[ 32.845346] ? kthread_create_on_node+0x70/0x70
[ 32.845347] ? kthread_create_on_node+0x70/0x70
[ 32.845349] ret_from_fork+0x2a/0x40
[ 32.845555] pci 0000:02:00.0: [8086:1576] type 01 class 0x060400
[ 32.845621] pci 0000:02:00.0: enabling Extended Tags
[ 32.845711] pci 0000:02:00.0: supports D1 D2
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