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    memblock: make for_each_mem_range() traverse MEMBLOCK_HOTPLUG regions · 79e482e9
    Mike Rapoport authored
    Commit b10d6bca ("arch, drivers: replace for_each_membock() with
    for_each_mem_range()") didn't take into account that when there is
    movable_node parameter in the kernel command line, for_each_mem_range()
    would skip ranges marked with MEMBLOCK_HOTPLUG.
    
    The page table setup code in POWER uses for_each_mem_range() to create
    the linear mapping of the physical memory and since the regions marked
    as MEMORY_HOTPLUG are skipped, they never make it to the linear map.
    
    A later access to the memory in those ranges will fail:
    
      BUG: Unable to handle kernel data access on write at 0xc000000400000000
      Faulting instruction address: 0xc00000000008a3c0
      Oops: Kernel access of bad area, sig: 11 [#1]
      LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
      Modules linked in:
      CPU: 0 PID: 53 Comm: kworker/u2:0 Not tainted 5.13.0 #7
      NIP:  c00000000008a3c0 LR: c0000000003c1ed8 CTR: 0000000000000040
      REGS: c000000008a57770 TRAP: 0300   Not tainted  (5.13.0)
      MSR:  8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE>  CR: 84222202  XER: 20040000
      CFAR: c0000000003c1ed4 DAR: c000000400000000 DSISR: 42000000 IRQMASK: 0
      GPR00: c0000000003c1ed8 c000000008a57a10 c0000000019da700 c000000400000000
      GPR04: 0000000000000280 0000000000000180 0000000000000400 0000000000000200
      GPR08: 0000000000000100 0000000000000080 0000000000000040 0000000000000300
      GPR12: 0000000000000380 c000000001bc0000 c0000000001660c8 c000000006337e00
      GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
      GPR20: 0000000040000000 0000000020000000 c000000001a81990 c000000008c30000
      GPR24: c000000008c20000 c000000001a81998 000fffffffff0000 c000000001a819a0
      GPR28: c000000001a81908 c00c000001000000 c000000008c40000 c000000008a64680
      NIP clear_user_page+0x50/0x80
      LR __handle_mm_fault+0xc88/0x1910
      Call Trace:
        __handle_mm_fault+0xc44/0x1910 (unreliable)
        handle_mm_fault+0x130/0x2a0
        __get_user_pages+0x248/0x610
        __get_user_pages_remote+0x12c/0x3e0
        get_arg_page+0x54/0xf0
        copy_string_kernel+0x11c/0x210
        kernel_execve+0x16c/0x220
        call_usermodehelper_exec_async+0x1b0/0x2f0
        ret_from_kernel_thread+0x5c/0x70
      Instruction dump:
      79280fa4 79271764 79261f24 794ae8e2 7ca94214 7d683a14 7c893a14 7d893050
      7d4903a6 60000000 60000000 60000000 <7c001fec> 7c091fec 7c081fec 7c051fec
      ---[ end trace 490b8c67e6075e09 ]---
    
    Making for_each_mem_range() include MEMBLOCK_HOTPLUG regions in the
    traversal fixes this issue.
    
    Link: https://bugzilla.redhat.com/show_bug.cgi?id=1976100
    Link: https://lkml.kernel.org/r/20210712071132.20902-1-rppt@kernel.org
    Fixes: b10d6bca
    
     ("arch, drivers: replace for_each_membock() with for_each_mem_range()")
    Signed-off-by: default avatarMike Rapoport <rppt@linux.ibm.com>
    Tested-by: default avatarGreg Kurz <groug@kaod.org>
    Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
    Cc: <stable@vger.kernel.org>	[5.10+]
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    79e482e9