On linux -next, after onlining hotpluged memory:
======================================================
WARNING: possible circular locking dependency detected
4.12.0-rc6-next-20170626+ #761 Not tainted
------------------------------------------------------
kworker/u8:0/5 is trying to acquire lock:
(cpu_hotplug_lock.rw_sem){++++++}, at: [<ffffffff812df34c>] stop_machine+0x1c/0x40
but task is already holding lock:
(zonelists_mutex){+.+.+.}, at: [<ffffffff836e3e7d>] online_pages+0x3bd/0x720
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (zonelists_mutex){+.+.+.}:
__lock_acquire+0x1d1a/0x3120
lock_acquire+0x10d/0x310
__mutex_lock+0xcd/0x12d0
mutex_lock_nested+0x1b/0x20
online_pages+0x3bd/0x720
memory_subsys_online+0x32b/0x4f0
device_online+0xfa/0x170
online_memory_block+0x12/0x20
walk_memory_range+0xe9/0x190
add_memory_resource+0x2c6/0x350
add_memory+0x12c/0x1d0
acpi_memory_device_add+0x339/0x9e0
acpi_bus_attach+0x325/0x810
acpi_bus_scan+0x7e/0xd0
acpi_device_hotplug+0x2d9/0x910
acpi_hotplug_work_fn+0x5e/0x90
process_one_work+0x68c/0x16b0
worker_thread+0xde/0x11c0
kthread+0x2d6/0x3d0
ret_from_fork+0x27/0x40
-> #1 (mem_hotplug.lock#2){+.+.+.}:
__lock_acquire+0x1d1a/0x3120
lock_acquire+0x10d/0x310
__mutex_lock+0xcd/0x12d0
mutex_lock_nested+0x1b/0x20
get_online_mems+0x4c/0x70
kmem_cache_create+0x30/0x290
ptlock_cache_init+0x24/0x2d
start_kernel+0x267/0x5ec
x86_64_start_reservations+0x2f/0x31
x86_64_start_kernel+0x143/0x152
verify_cpu+0x0/0xf1
-> #0 (cpu_hotplug_lock.rw_sem){++++++}:
check_prevs_add+0x1c0/0x1b30
__lock_acquire+0x1d1a/0x3120
lock_acquire+0x10d/0x310
cpus_read_lock+0x2a/0x60
stop_machine+0x1c/0x40
build_all_zonelists+0x80/0x1c1
online_pages+0x6c2/0x720
memory_subsys_online+0x32b/0x4f0
device_online+0xfa/0x170
online_memory_block+0x12/0x20
walk_memory_range+0xe9/0x190
add_memory_resource+0x2c6/0x350
add_memory+0x12c/0x1d0
acpi_memory_device_add+0x339/0x9e0
acpi_bus_attach+0x325/0x810
acpi_bus_scan+0x7e/0xd0
acpi_device_hotplug+0x2d9/0x910
acpi_hotplug_work_fn+0x5e/0x90
process_one_work+0x68c/0x16b0
worker_thread+0xde/0x11c0
kthread+0x2d6/0x3d0
ret_from_fork+0x27/0x40
other info that might help us debug this:
Chain exists of:
cpu_hotplug_lock.rw_sem --> mem_hotplug.lock#2 --> zonelists_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(zonelists_mutex);
lock(mem_hotplug.lock#2);
lock(zonelists_mutex);
lock(cpu_hotplug_lock.rw_sem);
*** DEADLOCK ***
9 locks held by kworker/u8:0/5:
#0: ("kacpi_hotplug"){.+.+.+}, at: [<ffffffff81142c97>] process_one_work+0x5b7/0x16b0
#1: ((&hpw->work)){+.+.+.}, at: [<ffffffff81142cc4>] process_one_work+0x5e4/0x16b0
#2: (device_hotplug_lock){+.+.+.}, at: [<ffffffff82555427>] lock_device_hotplug+0x17/0x20
#3: (acpi_scan_lock){+.+.+.}, at: [<ffffffff822544cb>] acpi_device_hotplug+0x7b/0x910
#4: (memory_add_remove_lock){+.+.+.}, at: [<ffffffff81583ab1>] mem_hotplug_begin+0x31/0xc0
#5: (mem_hotplug.lock){++++++}, at: [<ffffffff81583a85>] mem_hotplug_begin+0x5/0xc0
#6: (mem_hotplug.lock#2){+.+.+.}, at: [<ffffffff81583af2>] mem_hotplug_begin+0x72/0xc0
#7: (&dev->mutex){......}, at: [<ffffffff82559611>] device_online+0x21/0x170
#8: (zonelists_mutex){+.+.+.}, at: [<ffffffff836e3e7d>] online_pages+0x3bd/0x720
stack backtrace:
CPU: 2 PID: 5 Comm: kworker/u8:0 Not tainted 4.12.0-rc6-next-20170626+ #761
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
Workqueue: kacpi_hotplug acpi_hotplug_work_fn
Call Trace:
dump_stack+0x67/0x99
print_circular_bug+0x33c/0x650
check_prevs_add+0x1c0/0x1b30
__lock_acquire+0x1d1a/0x3120
lock_acquire+0x10d/0x310
cpus_read_lock+0x2a/0x60
stop_machine+0x1c/0x40
build_all_zonelists+0x80/0x1c1
online_pages+0x6c2/0x720
memory_subsys_online+0x32b/0x4f0
device_online+0xfa/0x170
online_memory_block+0x12/0x20
walk_memory_range+0xe9/0x190
add_memory_resource+0x2c6/0x350
add_memory+0x12c/0x1d0
acpi_memory_device_add+0x339/0x9e0
acpi_bus_attach+0x325/0x810
acpi_bus_scan+0x7e/0xd0
acpi_device_hotplug+0x2d9/0x910
acpi_hotplug_work_fn+0x5e/0x90
process_one_work+0x68c/0x16b0
worker_thread+0xde/0x11c0
kthread+0x2d6/0x3d0
ret_from_fork+0x27/0x40
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
