• Yinghai Lu's avatar
    mm: check if section present during memory block registering · d6046ed0
    Yinghai Lu authored
    commit 04697858 upstream.
    
    Tony Luck found on his setup, if memory block size 512M will cause crash
    during booting.
    
      BUG: unable to handle kernel paging request at ffffea0074000020
      IP: get_nid_for_pfn+0x17/0x40
      PGD 128ffcb067 PUD 128ffc9067 PMD 0
      Oops: 0000 [#1] SMP
      Modules linked in:
      CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.2.0-rc8 #1
      ...
      Call Trace:
         ? register_mem_sect_under_node+0x66/0xe0
         register_one_node+0x17b/0x240
         ? pci_iommu_alloc+0x6e/0x6e
         topology_init+0x3c/0x95
         do_one_initcall+0xcd/0x1f0
    
    The system has non continuous RAM address:
     BIOS-e820: [mem 0x0000001300000000-0x0000001cffffffff] usable
     BIOS-e820: [mem 0x0000001d70000000-0x0000001ec7ffefff] usable
     BIOS-e820: [mem 0x0000001f00000000-0x0000002bffffffff] usable
     BIOS-e820: [mem 0x0000002c18000000-0x0000002d6fffefff] usable
     BIOS-e820: [mem 0x0000002e00000000-0x00000039ffffffff] usable
    
    So there are start sections in memory block not present.  For example:
    
        memory block : [0x2c18000000, 0x2c20000000) 512M
    
    first three sections are not present.
    
    The current register_mem_sect_under_node() assume first section is
    present, but memory block section number range [start_section_nr,
    end_section_nr] would include not present section.
    
    For arch that support vmemmap, we don't setup memmap for struct page
    area within not present sections area.
    
    So skip the pfn range that belong to absent section.
    
    [akpm@linux-foundation.org: simplification]
    [rientjes@google.com: more simplification]
    Fixes: bdee237c ("x86: mm: Use 2GB memory block size on large memory x86-64 systems")
    Fixes: 982792c7 ("x86, mm: probe memory block size for generic x86 64bit")
    Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
    Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
    Reported-by: default avatarTony Luck <tony.luck@intel.com>
    Tested-by: default avatarTony Luck <tony.luck@intel.com>
    Cc: Greg KH <greg@kroah.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    Tested-by: default avatarDavid Rientjes <rientjes@google.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
    d6046ed0
node.c 18.8 KB