<feed xmlns='http://www.w3.org/2005/Atom'>
<title>user/sven/linux.git/mm/memory_hotplug.c, branch v4.19.312</title>
<subtitle>Linux Kernel
</subtitle>
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<updated>2021-09-22T09:48:12Z</updated>
<entry>
<title>mm/memory_hotplug: use "unsigned long" for PFN in zone_for_pfn_range()</title>
<updated>2021-09-22T09:48:12Z</updated>
<author>
<name>David Hildenbrand</name>
<email>david@redhat.com</email>
</author>
<published>2021-09-08T02:54:59Z</published>
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commit 7cf209ba8a86410939a24cb1aeb279479a7e0ca6 upstream.

Patch series "mm/memory_hotplug: preparatory patches for new online policy and memory"

These are all cleanups and one fix previously sent as part of [1]:
[PATCH v1 00/12] mm/memory_hotplug: "auto-movable" online policy and memory
groups.

These patches make sense even without the other series, therefore I pulled
them out to make the other series easier to digest.

[1] https://lkml.kernel.org/r/20210607195430.48228-1-david@redhat.com

This patch (of 4):

Checkpatch complained on a follow-up patch that we are using "unsigned"
here, which defaults to "unsigned int" and checkpatch is correct.

As we will search for a fitting zone using the wrong pfn, we might end
up onlining memory to one of the special kernel zones, such as ZONE_DMA,
which can end badly as the onlined memory does not satisfy properties of
these zones.

Use "unsigned long" instead, just as we do in other places when handling
PFNs.  This can bite us once we have physical addresses in the range of
multiple TB.

Link: https://lkml.kernel.org/r/20210712124052.26491-2-david@redhat.com
Fixes: e5e689302633 ("mm, memory_hotplug: display allowed zones in the preferred ordering")
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Reviewed-by: Pankaj Gupta &lt;pankaj.gupta@ionos.com&gt;
Reviewed-by: Muchun Song &lt;songmuchun@bytedance.com&gt;
Reviewed-by: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: David Hildenbrand &lt;david@redhat.com&gt;
Cc: Vitaly Kuznetsov &lt;vkuznets@redhat.com&gt;
Cc: "Michael S. Tsirkin" &lt;mst@redhat.com&gt;
Cc: Jason Wang &lt;jasowang@redhat.com&gt;
Cc: Pankaj Gupta &lt;pankaj.gupta.linux@gmail.com&gt;
Cc: Wei Yang &lt;richard.weiyang@linux.alibaba.com&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Mike Rapoport &lt;rppt@kernel.org&gt;
Cc: "Rafael J. Wysocki" &lt;rjw@rjwysocki.net&gt;
Cc: Len Brown &lt;lenb@kernel.org&gt;
Cc: Pavel Tatashin &lt;pasha.tatashin@soleen.com&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: virtualization@lists.linux-foundation.org
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: "Aneesh Kumar K.V" &lt;aneesh.kumar@linux.ibm.com&gt;
Cc: Anton Blanchard &lt;anton@ozlabs.org&gt;
Cc: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Baoquan He &lt;bhe@redhat.com&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Christian Borntraeger &lt;borntraeger@de.ibm.com&gt;
Cc: Christophe Leroy &lt;christophe.leroy@c-s.fr&gt;
Cc: Dave Jiang &lt;dave.jiang@intel.com&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jia He &lt;justin.he@arm.com&gt;
Cc: Joe Perches &lt;joe@perches.com&gt;
Cc: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Cc: Laurent Dufour &lt;ldufour@linux.ibm.com&gt;
Cc: Michel Lespinasse &lt;michel@lespinasse.org&gt;
Cc: Nathan Lynch &lt;nathanl@linux.ibm.com&gt;
Cc: Nicholas Piggin &lt;npiggin@gmail.com&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Pierre Morel &lt;pmorel@linux.ibm.com&gt;
Cc: "Rafael J. Wysocki" &lt;rafael.j.wysocki@intel.com&gt;
Cc: Rich Felker &lt;dalias@libc.org&gt;
Cc: Scott Cheloha &lt;cheloha@linux.ibm.com&gt;
Cc: Sergei Trofimovich &lt;slyfox@gentoo.org&gt;
Cc: Thiago Jung Bauermann &lt;bauerman@linux.ibm.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Cc: Vishal Verma &lt;vishal.l.verma@intel.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm: don't rely on system state to detect hot-plug operations</title>
<updated>2020-10-07T06:00:08Z</updated>
<author>
<name>Laurent Dufour</name>
<email>ldufour@linux.ibm.com</email>
</author>
<published>2020-09-26T04:19:31Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=b6f69f72c15d7f973f5709c5351f378f235b3654'/>
<id>urn:sha1:b6f69f72c15d7f973f5709c5351f378f235b3654</id>
<content type='text'>
commit f85086f95fa36194eb0db5cd5c12e56801b98523 upstream.

In register_mem_sect_under_node() the system_state's value is checked to
detect whether the call is made during boot time or during an hot-plug
operation.  Unfortunately, that check against SYSTEM_BOOTING is wrong
because regular memory is registered at SYSTEM_SCHEDULING state.  In
addition, memory hot-plug operation can be triggered at this system
state by the ACPI [1].  So checking against the system state is not
enough.

The consequence is that on system with interleaved node's ranges like this:

 Early memory node ranges
   node   1: [mem 0x0000000000000000-0x000000011fffffff]
   node   2: [mem 0x0000000120000000-0x000000014fffffff]
   node   1: [mem 0x0000000150000000-0x00000001ffffffff]
   node   0: [mem 0x0000000200000000-0x000000048fffffff]
   node   2: [mem 0x0000000490000000-0x00000007ffffffff]

This can be seen on PowerPC LPAR after multiple memory hot-plug and
hot-unplug operations are done.  At the next reboot the node's memory
ranges can be interleaved and since the call to link_mem_sections() is
made in topology_init() while the system is in the SYSTEM_SCHEDULING
state, the node's id is not checked, and the sections registered to
multiple nodes:

  $ ls -l /sys/devices/system/memory/memory21/node*
  total 0
  lrwxrwxrwx 1 root root     0 Aug 24 05:27 node1 -&gt; ../../node/node1
  lrwxrwxrwx 1 root root     0 Aug 24 05:27 node2 -&gt; ../../node/node2

In that case, the system is able to boot but if later one of theses
memory blocks is hot-unplugged and then hot-plugged, the sysfs
inconsistency is detected and this is triggering a BUG_ON():

  kernel BUG at /Users/laurent/src/linux-ppc/mm/memory_hotplug.c:1084!
  Oops: Exception in kernel mode, sig: 5 [#1]
  LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in: rpadlpar_io rpaphp pseries_rng rng_core vmx_crypto gf128mul binfmt_misc ip_tables x_tables xfs libcrc32c crc32c_vpmsum autofs4
  CPU: 8 PID: 10256 Comm: drmgr Not tainted 5.9.0-rc1+ #25
  Call Trace:
    add_memory_resource+0x23c/0x340 (unreliable)
    __add_memory+0x5c/0xf0
    dlpar_add_lmb+0x1b4/0x500
    dlpar_memory+0x1f8/0xb80
    handle_dlpar_errorlog+0xc0/0x190
    dlpar_store+0x198/0x4a0
    kobj_attr_store+0x30/0x50
    sysfs_kf_write+0x64/0x90
    kernfs_fop_write+0x1b0/0x290
    vfs_write+0xe8/0x290
    ksys_write+0xdc/0x130
    system_call_exception+0x160/0x270
    system_call_common+0xf0/0x27c

This patch addresses the root cause by not relying on the system_state
value to detect whether the call is due to a hot-plug operation.  An
extra parameter is added to link_mem_sections() detailing whether the
operation is due to a hot-plug operation.

[1] According to Oscar Salvador, using this qemu command line, ACPI
memory hotplug operations are raised at SYSTEM_SCHEDULING state:

  $QEMU -enable-kvm -machine pc -smp 4,sockets=4,cores=1,threads=1 -cpu host -monitor pty \
        -m size=$MEM,slots=255,maxmem=4294967296k  \
        -numa node,nodeid=0,cpus=0-3,mem=512 -numa node,nodeid=1,mem=512 \
        -object memory-backend-ram,id=memdimm0,size=134217728 -device pc-dimm,node=0,memdev=memdimm0,id=dimm0,slot=0 \
        -object memory-backend-ram,id=memdimm1,size=134217728 -device pc-dimm,node=0,memdev=memdimm1,id=dimm1,slot=1 \
        -object memory-backend-ram,id=memdimm2,size=134217728 -device pc-dimm,node=0,memdev=memdimm2,id=dimm2,slot=2 \
        -object memory-backend-ram,id=memdimm3,size=134217728 -device pc-dimm,node=0,memdev=memdimm3,id=dimm3,slot=3 \
        -object memory-backend-ram,id=memdimm4,size=134217728 -device pc-dimm,node=1,memdev=memdimm4,id=dimm4,slot=4 \
        -object memory-backend-ram,id=memdimm5,size=134217728 -device pc-dimm,node=1,memdev=memdimm5,id=dimm5,slot=5 \
        -object memory-backend-ram,id=memdimm6,size=134217728 -device pc-dimm,node=1,memdev=memdimm6,id=dimm6,slot=6 \

Fixes: 4fbce633910e ("mm/memory_hotplug.c: make register_mem_sect_under_node() a callback of walk_memory_range()")
Signed-off-by: Laurent Dufour &lt;ldufour@linux.ibm.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Reviewed-by: David Hildenbrand &lt;david@redhat.com&gt;
Reviewed-by: Oscar Salvador &lt;osalvador@suse.de&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: "Rafael J. Wysocki" &lt;rafael@kernel.org&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: Nathan Lynch &lt;nathanl@linux.ibm.com&gt;
Cc: Scott Cheloha &lt;cheloha@linux.ibm.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lkml.kernel.org/r/20200915094143.79181-3-ldufour@linux.ibm.com
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm: replace memmap_context by meminit_context</title>
<updated>2020-10-07T06:00:08Z</updated>
<author>
<name>Laurent Dufour</name>
<email>ldufour@linux.ibm.com</email>
</author>
<published>2020-09-26T04:19:28Z</published>
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<id>urn:sha1:25eaea1b33f2569f69a82dfddb3fb05384143bd0</id>
<content type='text'>
commit c1d0da83358a2316d9be7f229f26126dbaa07468 upstream.

Patch series "mm: fix memory to node bad links in sysfs", v3.

Sometimes, firmware may expose interleaved memory layout like this:

 Early memory node ranges
   node   1: [mem 0x0000000000000000-0x000000011fffffff]
   node   2: [mem 0x0000000120000000-0x000000014fffffff]
   node   1: [mem 0x0000000150000000-0x00000001ffffffff]
   node   0: [mem 0x0000000200000000-0x000000048fffffff]
   node   2: [mem 0x0000000490000000-0x00000007ffffffff]

In that case, we can see memory blocks assigned to multiple nodes in
sysfs:

  $ ls -l /sys/devices/system/memory/memory21
  total 0
  lrwxrwxrwx 1 root root     0 Aug 24 05:27 node1 -&gt; ../../node/node1
  lrwxrwxrwx 1 root root     0 Aug 24 05:27 node2 -&gt; ../../node/node2
  -rw-r--r-- 1 root root 65536 Aug 24 05:27 online
  -r--r--r-- 1 root root 65536 Aug 24 05:27 phys_device
  -r--r--r-- 1 root root 65536 Aug 24 05:27 phys_index
  drwxr-xr-x 2 root root     0 Aug 24 05:27 power
  -r--r--r-- 1 root root 65536 Aug 24 05:27 removable
  -rw-r--r-- 1 root root 65536 Aug 24 05:27 state
  lrwxrwxrwx 1 root root     0 Aug 24 05:25 subsystem -&gt; ../../../../bus/memory
  -rw-r--r-- 1 root root 65536 Aug 24 05:25 uevent
  -r--r--r-- 1 root root 65536 Aug 24 05:27 valid_zones

The same applies in the node's directory with a memory21 link in both
the node1 and node2's directory.

This is wrong but doesn't prevent the system to run.  However when
later, one of these memory blocks is hot-unplugged and then hot-plugged,
the system is detecting an inconsistency in the sysfs layout and a
BUG_ON() is raised:

  kernel BUG at /Users/laurent/src/linux-ppc/mm/memory_hotplug.c:1084!
  LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in: rpadlpar_io rpaphp pseries_rng rng_core vmx_crypto gf128mul binfmt_misc ip_tables x_tables xfs libcrc32c crc32c_vpmsum autofs4
  CPU: 8 PID: 10256 Comm: drmgr Not tainted 5.9.0-rc1+ #25
  Call Trace:
    add_memory_resource+0x23c/0x340 (unreliable)
    __add_memory+0x5c/0xf0
    dlpar_add_lmb+0x1b4/0x500
    dlpar_memory+0x1f8/0xb80
    handle_dlpar_errorlog+0xc0/0x190
    dlpar_store+0x198/0x4a0
    kobj_attr_store+0x30/0x50
    sysfs_kf_write+0x64/0x90
    kernfs_fop_write+0x1b0/0x290
    vfs_write+0xe8/0x290
    ksys_write+0xdc/0x130
    system_call_exception+0x160/0x270
    system_call_common+0xf0/0x27c

This has been seen on PowerPC LPAR.

The root cause of this issue is that when node's memory is registered,
the range used can overlap another node's range, thus the memory block
is registered to multiple nodes in sysfs.

There are two issues here:

 (a) The sysfs memory and node's layouts are broken due to these
     multiple links

 (b) The link errors in link_mem_sections() should not lead to a system
     panic.

To address (a) register_mem_sect_under_node should not rely on the
system state to detect whether the link operation is triggered by a hot
plug operation or not.  This is addressed by the patches 1 and 2 of this
series.

Issue (b) will be addressed separately.

This patch (of 2):

The memmap_context enum is used to detect whether a memory operation is
due to a hot-add operation or happening at boot time.

Make it general to the hotplug operation and rename it as
meminit_context.

There is no functional change introduced by this patch

Suggested-by: David Hildenbrand &lt;david@redhat.com&gt;
Signed-off-by: Laurent Dufour &lt;ldufour@linux.ibm.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Reviewed-by: David Hildenbrand &lt;david@redhat.com&gt;
Reviewed-by: Oscar Salvador &lt;osalvador@suse.de&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: "Rafael J . Wysocki" &lt;rafael@kernel.org&gt;
Cc: Nathan Lynch &lt;nathanl@linux.ibm.com&gt;
Cc: Scott Cheloha &lt;cheloha@linux.ibm.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lkml.kernel.org/r/20200915094143.79181-1-ldufour@linux.ibm.com
Link: https://lkml.kernel.org/r/20200915132624.9723-1-ldufour@linux.ibm.com
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm/memory_hotplug: fix remove_memory() lockdep splat</title>
<updated>2020-02-11T12:33:56Z</updated>
<author>
<name>Dan Williams</name>
<email>dan.j.williams@intel.com</email>
</author>
<published>2020-01-31T06:11:17Z</published>
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<id>urn:sha1:9a6873a9868c4791b2d281319c7dbd3ae7dccba6</id>
<content type='text'>
commit f1037ec0cc8ac1a450974ad9754e991f72884f48 upstream.

The daxctl unit test for the dax_kmem driver currently triggers the
(false positive) lockdep splat below.  It results from the fact that
remove_memory_block_devices() is invoked under the mem_hotplug_lock()
causing lockdep entanglements with cpu_hotplug_lock() and sysfs (kernfs
active state tracking).  It is a false positive because the sysfs
attribute path triggering the memory remove is not the same attribute
path associated with memory-block device.

sysfs_break_active_protection() is not applicable since there is no real
deadlock conflict, instead move memory-block device removal outside the
lock.  The mem_hotplug_lock() is not needed to synchronize the
memory-block device removal vs the page online state, that is already
handled by lock_device_hotplug().  Specifically, lock_device_hotplug()
is sufficient to allow try_remove_memory() to check the offline state of
the memblocks and be assured that any in progress online attempts are
flushed / blocked by kernfs_drain() / attribute removal.

The add_memory() path safely creates memblock devices under the
mem_hotplug_lock().  There is no kernfs active state synchronization in
the memblock device_register() path, so nothing to fix there.

This change is only possible thanks to the recent change that refactored
memory block device removal out of arch_remove_memory() (commit
4c4b7f9ba948 "mm/memory_hotplug: remove memory block devices before
arch_remove_memory()"), and David's due diligence tracking down the
guarantees afforded by kernfs_drain().  Not flagged for -stable since
this only impacts ongoing development and lockdep validation, not a
runtime issue.

    ======================================================
    WARNING: possible circular locking dependency detected
    5.5.0-rc3+ #230 Tainted: G           OE
    ------------------------------------------------------
    lt-daxctl/6459 is trying to acquire lock:
    ffff99c7f0003510 (kn-&gt;count#241){++++}, at: kernfs_remove_by_name_ns+0x41/0x80

    but task is already holding lock:
    ffffffffa76a5450 (mem_hotplug_lock.rw_sem){++++}, at: percpu_down_write+0x20/0xe0

    which lock already depends on the new lock.

    the existing dependency chain (in reverse order) is:

    -&gt; #2 (mem_hotplug_lock.rw_sem){++++}:
           __lock_acquire+0x39c/0x790
           lock_acquire+0xa2/0x1b0
           get_online_mems+0x3e/0xb0
           kmem_cache_create_usercopy+0x2e/0x260
           kmem_cache_create+0x12/0x20
           ptlock_cache_init+0x20/0x28
           start_kernel+0x243/0x547
           secondary_startup_64+0xb6/0xc0

    -&gt; #1 (cpu_hotplug_lock.rw_sem){++++}:
           __lock_acquire+0x39c/0x790
           lock_acquire+0xa2/0x1b0
           cpus_read_lock+0x3e/0xb0
           online_pages+0x37/0x300
           memory_subsys_online+0x17d/0x1c0
           device_online+0x60/0x80
           state_store+0x65/0xd0
           kernfs_fop_write+0xcf/0x1c0
           vfs_write+0xdb/0x1d0
           ksys_write+0x65/0xe0
           do_syscall_64+0x5c/0xa0
           entry_SYSCALL_64_after_hwframe+0x49/0xbe

    -&gt; #0 (kn-&gt;count#241){++++}:
           check_prev_add+0x98/0xa40
           validate_chain+0x576/0x860
           __lock_acquire+0x39c/0x790
           lock_acquire+0xa2/0x1b0
           __kernfs_remove+0x25f/0x2e0
           kernfs_remove_by_name_ns+0x41/0x80
           remove_files.isra.0+0x30/0x70
           sysfs_remove_group+0x3d/0x80
           sysfs_remove_groups+0x29/0x40
           device_remove_attrs+0x39/0x70
           device_del+0x16a/0x3f0
           device_unregister+0x16/0x60
           remove_memory_block_devices+0x82/0xb0
           try_remove_memory+0xb5/0x130
           remove_memory+0x26/0x40
           dev_dax_kmem_remove+0x44/0x6a [kmem]
           device_release_driver_internal+0xe4/0x1c0
           unbind_store+0xef/0x120
           kernfs_fop_write+0xcf/0x1c0
           vfs_write+0xdb/0x1d0
           ksys_write+0x65/0xe0
           do_syscall_64+0x5c/0xa0
           entry_SYSCALL_64_after_hwframe+0x49/0xbe

    other info that might help us debug this:

    Chain exists of:
      kn-&gt;count#241 --&gt; cpu_hotplug_lock.rw_sem --&gt; mem_hotplug_lock.rw_sem

     Possible unsafe locking scenario:

           CPU0                    CPU1
           ----                    ----
      lock(mem_hotplug_lock.rw_sem);
                                   lock(cpu_hotplug_lock.rw_sem);
                                   lock(mem_hotplug_lock.rw_sem);
      lock(kn-&gt;count#241);

     *** DEADLOCK ***

No fixes tag as this has been a long standing issue that predated the
addition of kernfs lockdep annotations.

Link: http://lkml.kernel.org/r/157991441887.2763922.4770790047389427325.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Reviewed-by: David Hildenbrand &lt;david@redhat.com&gt;
Cc: Vishal Verma &lt;vishal.l.verma@intel.com&gt;
Cc: Pavel Tatashin &lt;pasha.tatashin@soleen.com&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>mm/memory_hotplug: shrink zones when offlining memory</title>
<updated>2020-01-29T15:43:27Z</updated>
<author>
<name>David Hildenbrand</name>
<email>david@redhat.com</email>
</author>
<published>2020-01-28T09:50:21Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=86834898d5a5e5aef9ae6d285201f2d99a4eb300'/>
<id>urn:sha1:86834898d5a5e5aef9ae6d285201f2d99a4eb300</id>
<content type='text'>
commit feee6b2989165631b17ac6d4ccdbf6759254e85a upstream.

-- snip --

- Missing arm64 hot(un)plug support
- Missing some vmem_altmap_offset() cleanups
- Missing sub-section hotadd support
- Missing unification of mm/hmm.c and kernel/memremap.c

-- snip --

We currently try to shrink a single zone when removing memory.  We use
the zone of the first page of the memory we are removing.  If that
memmap was never initialized (e.g., memory was never onlined), we will
read garbage and can trigger kernel BUGs (due to a stale pointer):

    BUG: unable to handle page fault for address: 000000000000353d
    #PF: supervisor write access in kernel mode
    #PF: error_code(0x0002) - not-present page
    PGD 0 P4D 0
    Oops: 0002 [#1] SMP PTI
    CPU: 1 PID: 7 Comm: kworker/u8:0 Not tainted 5.3.0-rc5-next-20190820+ #317
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.4
    Workqueue: kacpi_hotplug acpi_hotplug_work_fn
    RIP: 0010:clear_zone_contiguous+0x5/0x10
    Code: 48 89 c6 48 89 c3 e8 2a fe ff ff 48 85 c0 75 cf 5b 5d c3 c6 85 fd 05 00 00 01 5b 5d c3 0f 1f 840
    RSP: 0018:ffffad2400043c98 EFLAGS: 00010246
    RAX: 0000000000000000 RBX: 0000000200000000 RCX: 0000000000000000
    RDX: 0000000000200000 RSI: 0000000000140000 RDI: 0000000000002f40
    RBP: 0000000140000000 R08: 0000000000000000 R09: 0000000000000001
    R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000140000
    R13: 0000000000140000 R14: 0000000000002f40 R15: ffff9e3e7aff3680
    FS:  0000000000000000(0000) GS:ffff9e3e7bb00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 000000000000353d CR3: 0000000058610000 CR4: 00000000000006e0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
    Call Trace:
     __remove_pages+0x4b/0x640
     arch_remove_memory+0x63/0x8d
     try_remove_memory+0xdb/0x130
     __remove_memory+0xa/0x11
     acpi_memory_device_remove+0x70/0x100
     acpi_bus_trim+0x55/0x90
     acpi_device_hotplug+0x227/0x3a0
     acpi_hotplug_work_fn+0x1a/0x30
     process_one_work+0x221/0x550
     worker_thread+0x50/0x3b0
     kthread+0x105/0x140
     ret_from_fork+0x3a/0x50
    Modules linked in:
    CR2: 000000000000353d

Instead, shrink the zones when offlining memory or when onlining failed.
Introduce and use remove_pfn_range_from_zone(() for that.  We now
properly shrink the zones, even if we have DIMMs whereby

 - Some memory blocks fall into no zone (never onlined)

 - Some memory blocks fall into multiple zones (offlined+re-onlined)

 - Multiple memory blocks that fall into different zones

Drop the zone parameter (with a potential dubious value) from
__remove_pages() and __remove_section().

Link: http://lkml.kernel.org/r/20191006085646.5768-6-david@redhat.com
Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online")	[visible after d0dc12e86b319]
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Reviewed-by: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: "Matthew Wilcox (Oracle)" &lt;willy@infradead.org&gt;
Cc: "Aneesh Kumar K.V" &lt;aneesh.kumar@linux.ibm.com&gt;
Cc: Pavel Tatashin &lt;pasha.tatashin@soleen.com&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[5.0+]
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm/memory_hotplug: fix try_offline_node()</title>
<updated>2020-01-29T15:43:27Z</updated>
<author>
<name>David Hildenbrand</name>
<email>david@redhat.com</email>
</author>
<published>2020-01-28T09:50:20Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=d98d053efa65169c4e29b8b477cd5bc2b7aef513'/>
<id>urn:sha1:d98d053efa65169c4e29b8b477cd5bc2b7aef513</id>
<content type='text'>
commit 2c91f8fc6c999fe10185d8ad99fda1759f662f70 upstream.

-- snip --

Only contextual issues:
- Unrelated check_and_unmap_cpu_on_node() changes are missing.
- Unrelated walk_memory_blocks() has not been moved/refactored yet.

-- snip --

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 f1dd2cd13c4b ("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 60a5a19e7419 ("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: 60a5a19e7419 ("memory-hotplug: remove sysfs file of node")
Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") # visiable after d0dc12e86b319
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Tested-by: Masayoshi Mizuma &lt;m.mizuma@jp.fujitsu.com&gt;
Cc: Tang Chen &lt;tangchen@cn.fujitsu.com&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: "Rafael J. Wysocki" &lt;rafael@kernel.org&gt;
Cc: Keith Busch &lt;keith.busch@intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: "Peter Zijlstra (Intel)" &lt;peterz@infradead.org&gt;
Cc: Jani Nikula &lt;jani.nikula@intel.com&gt;
Cc: Nayna Jain &lt;nayna@linux.ibm.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Pavel Tatashin &lt;pasha.tatashin@soleen.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm/hotplug: kill is_dev_zone() usage in __remove_pages()</title>
<updated>2020-01-29T15:43:26Z</updated>
<author>
<name>Dan Williams</name>
<email>dan.j.williams@intel.com</email>
</author>
<published>2020-01-28T09:50:17Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=b9cda6501a340c5d15487575a68454748e3132a4'/>
<id>urn:sha1:b9cda6501a340c5d15487575a68454748e3132a4</id>
<content type='text'>
commit 96da4350000973ef9310a10d077d65bbc017f093 upstream.

-- snip --

Minor conflict, keep the altmap check.

-- snip --

The zone type check was a leftover from the cleanup that plumbed altmap
through the memory hotplug path, i.e.  commit da024512a1fa "mm: pass the
vmem_altmap to arch_remove_memory and __remove_pages".

Link: http://lkml.kernel.org/r/156092352642.979959.6664333788149363039.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Reviewed-by: David Hildenbrand &lt;david@redhat.com&gt;
Reviewed-by: Oscar Salvador &lt;osalvador@suse.de&gt;
Tested-by: Aneesh Kumar K.V &lt;aneesh.kumar@linux.ibm.com&gt;	[ppc64]
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Cc: Pavel Tatashin &lt;pasha.tatashin@soleen.com&gt;
Cc: Jane Chu &lt;jane.chu@oracle.com&gt;
Cc: Jeff Moyer &lt;jmoyer@redhat.com&gt;
Cc: Jérôme Glisse &lt;jglisse@redhat.com&gt;
Cc: Jonathan Corbet &lt;corbet@lwn.net&gt;
Cc: Mike Rapoport &lt;rppt@linux.ibm.com&gt;
Cc: Toshi Kani &lt;toshi.kani@hpe.com&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Wei Yang &lt;richardw.yang@linux.intel.com&gt;
Cc: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm/memory_hotplug: remove "zone" parameter from sparse_remove_one_section</title>
<updated>2020-01-29T15:43:26Z</updated>
<author>
<name>David Hildenbrand</name>
<email>david@redhat.com</email>
</author>
<published>2020-01-28T09:50:16Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=dc6be8597c8c2959a7ba0c7cc809094d5dd8d99a'/>
<id>urn:sha1:dc6be8597c8c2959a7ba0c7cc809094d5dd8d99a</id>
<content type='text'>
commit b9bf8d342d9b443c0d19aa57883d8ddb38d965de upstream.

The parameter is unused, so let's drop it.  Memory removal paths should
never care about zones.  This is the job of memory offlining and will
require more refactorings.

Link: http://lkml.kernel.org/r/20190527111152.16324-12-david@redhat.com
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Reviewed-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Reviewed-by: Wei Yang &lt;richardw.yang@linux.intel.com&gt;
Reviewed-by: Oscar Salvador &lt;osalvador@suse.de&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: Andrew Banman &lt;andrew.banman@hpe.com&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Cc: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Cc: Arun KS &lt;arunks@codeaurora.org&gt;
Cc: Baoquan He &lt;bhe@redhat.com&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Chintan Pandya &lt;cpandya@codeaurora.org&gt;
Cc: Christophe Leroy &lt;christophe.leroy@c-s.fr&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Jonathan Cameron &lt;Jonathan.Cameron@huawei.com&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Cc: Jun Yao &lt;yaojun8558363@gmail.com&gt;
Cc: "Kirill A. Shutemov" &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Cc: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Cc: Mathieu Malaterre &lt;malat@debian.org&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Mike Rapoport &lt;rppt@linux.vnet.ibm.com&gt;
Cc: "mike.travis@hpe.com" &lt;mike.travis@hpe.com&gt;
Cc: Nicholas Piggin &lt;npiggin@gmail.com&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Pavel Tatashin &lt;pasha.tatashin@soleen.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Qian Cai &lt;cai@lca.pw&gt;
Cc: "Rafael J. Wysocki" &lt;rafael@kernel.org&gt;
Cc: Rich Felker &lt;dalias@libc.org&gt;
Cc: Rob Herring &lt;robh@kernel.org&gt;
Cc: Robin Murphy &lt;robin.murphy@arm.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&gt;
Cc: Yu Zhao &lt;yuzhao@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm/memory_hotplug: remove memory block devices before arch_remove_memory()</title>
<updated>2020-01-29T15:43:26Z</updated>
<author>
<name>David Hildenbrand</name>
<email>david@redhat.com</email>
</author>
<published>2020-01-28T09:50:14Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=d883abbc097e9e86ffba1342c6972ebdda06a127'/>
<id>urn:sha1:d883abbc097e9e86ffba1342c6972ebdda06a127</id>
<content type='text'>
commit 4c4b7f9ba9486c565aead99a198ceeef73ae81f6 upstream.

Let's factor out removing of memory block devices, which is only
necessary for memory added via add_memory() and friends that created
memory block devices.  Remove the devices before calling
arch_remove_memory().

This finishes factoring out memory block device handling from
arch_add_memory() and arch_remove_memory().

Link: http://lkml.kernel.org/r/20190527111152.16324-10-david@redhat.com
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Reviewed-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: "Rafael J. Wysocki" &lt;rafael@kernel.org&gt;
Cc: David Hildenbrand &lt;david@redhat.com&gt;
Cc: "mike.travis@hpe.com" &lt;mike.travis@hpe.com&gt;
Cc: Andrew Banman &lt;andrew.banman@hpe.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Jonathan Cameron &lt;Jonathan.Cameron@huawei.com&gt;
Cc: Arun KS &lt;arunks@codeaurora.org&gt;
Cc: Mathieu Malaterre &lt;malat@debian.org&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Cc: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Cc: Baoquan He &lt;bhe@redhat.com&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Chintan Pandya &lt;cpandya@codeaurora.org&gt;
Cc: Christophe Leroy &lt;christophe.leroy@c-s.fr&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Cc: Jun Yao &lt;yaojun8558363@gmail.com&gt;
Cc: "Kirill A. Shutemov" &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Mike Rapoport &lt;rppt@linux.vnet.ibm.com&gt;
Cc: Nicholas Piggin &lt;npiggin@gmail.com&gt;
Cc: Oscar Salvador &lt;osalvador@suse.com&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Pavel Tatashin &lt;pasha.tatashin@soleen.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Qian Cai &lt;cai@lca.pw&gt;
Cc: Rich Felker &lt;dalias@libc.org&gt;
Cc: Rob Herring &lt;robh@kernel.org&gt;
Cc: Robin Murphy &lt;robin.murphy@arm.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Cc: Wei Yang &lt;richard.weiyang@gmail.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&gt;
Cc: Yu Zhao &lt;yuzhao@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm/memory_hotplug: create memory block devices after arch_add_memory()</title>
<updated>2020-01-29T15:43:26Z</updated>
<author>
<name>David Hildenbrand</name>
<email>david@redhat.com</email>
</author>
<published>2020-01-28T09:50:13Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=aa49b6abcefc9baf8d254f75ed19c38b6866951f'/>
<id>urn:sha1:aa49b6abcefc9baf8d254f75ed19c38b6866951f</id>
<content type='text'>
commit db051a0dac13db24d58470d75cee0ce7c6b031a1 upstream.

Only memory to be added to the buddy and to be onlined/offlined by user
space using /sys/devices/system/memory/...  needs (and should have!)
memory block devices.

Factor out creation of memory block devices.  Create all devices after
arch_add_memory() succeeded.  We can later drop the want_memblock
parameter, because it is now effectively stale.

Only after memory block devices have been added, memory can be onlined
by user space.  This implies, that memory is not visible to user space
at all before arch_add_memory() succeeded.

While at it
 - use WARN_ON_ONCE instead of BUG_ON in moved unregister_memory()
 - introduce find_memory_block_by_id() to search via block id
 - Use find_memory_block_by_id() in init_memory_block() to catch
   duplicates

Link: http://lkml.kernel.org/r/20190527111152.16324-8-david@redhat.com
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Reviewed-by: Pavel Tatashin &lt;pasha.tatashin@soleen.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: "Rafael J. Wysocki" &lt;rafael@kernel.org&gt;
Cc: David Hildenbrand &lt;david@redhat.com&gt;
Cc: "mike.travis@hpe.com" &lt;mike.travis@hpe.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Andrew Banman &lt;andrew.banman@hpe.com&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Qian Cai &lt;cai@lca.pw&gt;
Cc: Wei Yang &lt;richard.weiyang@gmail.com&gt;
Cc: Arun KS &lt;arunks@codeaurora.org&gt;
Cc: Mathieu Malaterre &lt;malat@debian.org&gt;
Cc: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Cc: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Cc: Baoquan He &lt;bhe@redhat.com&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Chintan Pandya &lt;cpandya@codeaurora.org&gt;
Cc: Christophe Leroy &lt;christophe.leroy@c-s.fr&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: Jonathan Cameron &lt;Jonathan.Cameron@huawei.com&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Cc: Jun Yao &lt;yaojun8558363@gmail.com&gt;
Cc: "Kirill A. Shutemov" &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Cc: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Mike Rapoport &lt;rppt@linux.vnet.ibm.com&gt;
Cc: Nicholas Piggin &lt;npiggin@gmail.com&gt;
Cc: Oscar Salvador &lt;osalvador@suse.com&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Rich Felker &lt;dalias@libc.org&gt;
Cc: Rob Herring &lt;robh@kernel.org&gt;
Cc: Robin Murphy &lt;robin.murphy@arm.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&gt;
Cc: Yu Zhao &lt;yuzhao@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: David Hildenbrand &lt;david@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
</feed>
