1. 01 Feb, 2020 38 commits
  2. 29 Jan, 2020 2 commits
    • Greg Kroah-Hartman's avatar
      Linux 4.19.100 · 7cdefde3
      Greg Kroah-Hartman authored
      7cdefde3
    • David Hildenbrand's avatar
      mm/memory_hotplug: shrink zones when offlining memory · 86834898
      David Hildenbrand authored
      commit feee6b29 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: f1dd2cd1 ("mm, memory_hotplug: do not associate hotadded memory to zones until online")	[visible after d0dc12e8]
      Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
      Reviewed-by: default avatarOscar Salvador <osalvador@suse.de>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
      Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
      Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Dan Williams <dan.j.williams@intel.com>
      Cc: Logan Gunthorpe <logang@deltatee.com>
      Cc: <stable@vger.kernel.org>	[5.0+]
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      86834898