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1 Commits

Author SHA1 Message Date
Tao Liu
0feb109818 check for invalid physical address of /proc/kcore when finding max_paddr
Backport from upstream.

commit 38d921a2ef50ebd36258097553626443ffe27496
Author: Coiby Xu <coxu@redhat.com>
Date:   Tue Jun 15 18:26:31 2021 +0800

    [PATCH] check for invalid physical address of /proc/kcore when finding max_paddr

    Kernel commit 464920104bf7adac12722035bfefb3d772eb04d8 ("/proc/kcore:
    update physical address for kcore ram and text") sets an invalid paddr
    (0xffffffffffffffff = -1) for PT_LOAD segments of not direct mapped
    regions:

      $ readelf -l /proc/kcore
      ...
      Program Headers:
        Type           Offset             VirtAddr           PhysAddr
                       FileSiz            MemSiz              Flags  Align
        NOTE           0x0000000000000120 0x0000000000000000 0x0000000000000000
                       0x0000000000002320 0x0000000000000000         0x0
        LOAD           0x1000000000010000 0xd000000000000000 0xffffffffffffffff
                                                             ^^^^^^^^^^^^^^^^^^
                       0x0001f80000000000 0x0001f80000000000  RWE    0x10000

    makedumpfile uses max_paddr to calculate the number of sections for
    sparse memory model thus wrong number is obtained based on max_paddr
    (-1).  This error could lead to the failure of copying /proc/kcore
    for RHEL-8.5 on ppc64le machine [1]:

      $ makedumpfile /proc/kcore vmcore1
      get_mem_section: Could not validate mem_section.
      get_mm_sparsemem: Can't get the address of mem_section.

      makedumpfile Failed.

    Let's check if the phys_start of the segment is a valid physical
    address to fix this problem.

    [1] https://bugzilla.redhat.com/show_bug.cgi?id=1965267

    Reported-by: Xiaoying Yan <yiyan@redhat.com>
    Signed-off-by: Coiby Xu <coxu@redhat.com>

Signed-off-by: Tao Liu <ltao@redhat.com>
Acked-by: Kairui Song <kasong@redhat.com>
2021-06-28 15:52:16 +08:00