linux_dsm_epyc7002/drivers/base
David Hildenbrand 2c91f8fc6c mm/memory_hotplug: fix try_offline_node()
try_offline_node() is pretty much broken right now:

 - The node span is updated when onlining memory, not when adding it. We
   ignore memory that was mever onlined. Bad.

 - We touch possible garbage memmaps. The pfn_to_nid(pfn) can easily
   trigger a kernel panic. Bad for memory that is offline but also bad
   for subsection hotadd with ZONE_DEVICE, whereby the memmap of the
   first PFN of a section might contain garbage.

 - Sections belonging to mixed nodes are not properly considered.

As memory blocks might belong to multiple nodes, we would have to walk
all pageblocks (or at least subsections) within present sections.
However, we don't have a way to identify whether a memmap that is not
online was initialized (relevant for ZONE_DEVICE).  This makes things
more complicated.

Luckily, we can piggy pack on the node span and the nid stored in memory
blocks.  Currently, the node span is grown when calling
move_pfn_range_to_zone() - e.g., when onlining memory, and shrunk when
removing memory, before calling try_offline_node().  Sysfs links are
created via link_mem_sections(), e.g., during boot or when adding
memory.

If the node still spans memory or if any memory block belongs to the
nid, we don't set the node offline.  As memory blocks that span multiple
nodes cannot get offlined, the nid stored in memory blocks is reliable
enough (for such online memory blocks, the node still spans the memory).

Introduce for_each_memory_block() to efficiently walk all memory blocks.

Note: We will soon stop shrinking the ZONE_DEVICE zone and the node span
when removing ZONE_DEVICE memory to fix similar issues (access of
garbage memmaps) - until we have a reliable way to identify whether
these memmaps were properly initialized.  This implies later, that once
a node had ZONE_DEVICE memory, we won't be able to set a node offline -
which should be acceptable.

Since commit f1dd2cd13c ("mm, memory_hotplug: do not associate
hotadded memory to zones until online") memory that is added is not
assoziated with a zone/node (memmap not initialized).  The introducing
commit 60a5a19e74 ("memory-hotplug: remove sysfs file of node")
already missed that we could have multiple nodes for a section and that
the zone/node span is updated when onlining pages, not when adding them.

I tested this by hotplugging two DIMMs to a memory-less and cpu-less
NUMA node.  The node is properly onlined when adding the DIMMs.  When
removing the DIMMs, the node is properly offlined.

Masayoshi Mizuma reported:

: Without this patch, memory hotplug fails as panic:
:
:  BUG: kernel NULL pointer dereference, address: 0000000000000000
:  ...
:  Call Trace:
:   remove_memory_block_devices+0x81/0xc0
:   try_remove_memory+0xb4/0x130
:   __remove_memory+0xa/0x20
:   acpi_memory_device_remove+0x84/0x100
:   acpi_bus_trim+0x57/0x90
:   acpi_bus_trim+0x2e/0x90
:   acpi_device_hotplug+0x2b2/0x4d0
:   acpi_hotplug_work_fn+0x1a/0x30
:   process_one_work+0x171/0x380
:   worker_thread+0x49/0x3f0
:   kthread+0xf8/0x130
:   ret_from_fork+0x35/0x40

[david@redhat.com: v3]
  Link: http://lkml.kernel.org/r/20191102120221.7553-1-david@redhat.com
Link: http://lkml.kernel.org/r/20191028105458.28320-1-david@redhat.com
Fixes: 60a5a19e74 ("memory-hotplug: remove sysfs file of node")
Fixes: f1dd2cd13c ("mm, memory_hotplug: do not associate hotadded memory to zones until online") # visiable after d0dc12e86b
Signed-off-by: David Hildenbrand <david@redhat.com>
Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Nayna Jain <nayna@linux.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15 18:34:00 -08:00
..
firmware_loader firmware: Fix missing inline 2019-07-23 10:20:25 +02:00
power PM: QoS: Drop frequency QoS types from device PM QoS 2019-10-21 02:05:21 +02:00
regmap regmap: Updates for v5.4 2019-09-16 13:57:02 -07:00
test drivers: base: test: add proper SPDX identifier to Makefile 2019-04-04 20:03:40 +02:00
arch_topology.c Power management updates for 5.4-rc1 2019-09-17 19:15:14 -07:00
attribute_container.c driver core: Remove redundant license text 2017-12-07 18:36:44 +01:00
base.h driver/core: Convert to use built-in RCU list checking 2019-08-13 14:28:47 -07:00
bus.c drivers: Introduce device lookup variants by name 2019-07-30 13:07:41 +02:00
cacheinfo.c Driver Core and debugfs changes for 5.3-rc1 2019-07-12 12:24:03 -07:00
class.c driver core: move device->knode_class to device_private 2019-01-18 16:55:48 +01:00
component.c drivers/component: kerneldoc polish 2019-02-19 13:20:35 +01:00
container.c driver core: Remove redundant license text 2017-12-07 18:36:44 +01:00
core.c cpufreq: Avoid cpufreq_suspend() deadlock on system shutdown 2019-10-10 11:11:17 +02:00
cpu.c x86/bugs: Add ITLB_MULTIHIT bug infrastructure 2019-11-04 12:22:01 +01:00
dd.c Revert "driver core: Add edit_links() callback for drivers" 2019-08-27 21:41:06 +02:00
devcon.c Merge generic_lookup_helpers into usb-next 2019-09-03 17:11:07 +02:00
devcoredump.c devcoredump: fix typo in comment 2019-08-15 17:38:11 +02:00
devres.c drivers/base/devres: introduce devm_release_action() 2019-06-13 17:34:56 -10:00
devtmpfs.c vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API 2019-09-12 21:05:34 -04:00
driver.c driver_find_device: Unify the match function with class_find_device() 2019-06-24 05:22:31 +02:00
firmware.c driver core: Remove redundant license text 2017-12-07 18:36:44 +01:00
hypervisor.c driver core: Remove redundant license text 2017-12-07 18:36:44 +01:00
init.c base: fix order of OF initialization 2018-07-07 17:54:29 +02:00
isa.c Merge 4.15-rc3 into driver-core-next 2017-12-11 08:50:05 +01:00
Kconfig base: arch_topology: update Kconfig help description 2019-07-22 09:36:44 -07:00
Makefile drivers: base: Introducing software nodes to the firmware node framework 2018-11-26 18:19:11 +01:00
map.c driver core: Remove redundant license text 2017-12-07 18:36:44 +01:00
memory.c mm/memory_hotplug: fix try_offline_node() 2019-11-15 18:34:00 -08:00
module.c driver core: Remove redundant license text 2017-12-07 18:36:44 +01:00
node.c mm,thp: stats for file backed THP 2019-09-24 15:54:11 -07:00
pinctrl.c driver core: Remove redundant license text 2017-12-07 18:36:44 +01:00
platform-msi.c platform-msi: Free descriptors in platform_msi_domain_free() 2018-12-13 09:35:31 +00:00
platform.c driver core: platform: Add platform_get_irq_byname_optional() 2019-10-07 12:52:44 +02:00
property.c device property: Introduce fwnode_find_reference() 2019-06-03 10:55:38 +02:00
soc.c base: soc: Export soc_device_register/unregister APIs 2019-08-05 14:56:31 -07:00
swnode.c software node: Initialize the return value in software_node_find_by_name() 2019-09-11 19:10:12 +02:00
syscore.c treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively 2019-04-09 14:19:06 +02:00
topology.c topology: Create core_cpus and die_cpus sysfs attributes 2019-05-23 10:08:34 +02:00
transport_class.c driver core: Remove redundant license text 2017-12-07 18:36:44 +01:00