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    elf: don't use MAP_FIXED_NOREPLACE for elf interpreter mappings · 9b2f72cc
    Chen Jingwen authored
    In commit b212921b ("elf: don't use MAP_FIXED_NOREPLACE for elf
    executable mappings") we still leave MAP_FIXED_NOREPLACE in place for
    Unfortunately, this will cause kernel to fail to start with:
        1 (init): Uhuuh, elf segment at 00003ffff7ffd000 requested but the memory is mapped already
        Failed to execute /init (error -17)
    The reason is that the elf interpreter (ld.so) has overlapping segments.
      readelf -l ld-2.31.so
      Program Headers:
        Type           Offset             VirtAddr           PhysAddr
                       FileSiz            MemSiz              Flags  Align
        LOAD           0x0000000000000000 0x0000000000000000 0x0000000000000000
                       0x000000000002c94c 0x000000000002c94c  R E    0x10000
        LOAD           0x000000000002dae0 0x000000000003dae0 0x000000000003dae0
                       0x00000000000021e8 0x0000000000002320  RW     0x10000
        LOAD           0x000000000002fe00 0x000000000003fe00 0x000000000003fe00
                       0x00000000000011ac 0x0000000000001328  RW     0x10000
    The reason for this problem is the same as described in commit
    ad55eac7 ("elf: enforce MAP_FIXED on overlaying elf segments").
    Not only executable binaries, elf interpreters (e.g. ld.so) can have
    overlapping elf segments, so we better drop MAP_FIXED_NOREPLACE and go
    back to MAP_FIXED in load_elf_interp.
    Fixes: 4ed28639
     ("fs, elf: drop MAP_FIXED usage from elf_map")
    Cc: <stable@vger.kernel.org> # v4.19
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Michal Hocko <mhocko@suse.com>
    Signed-off-by: default avatarChen Jingwen <chenjingwen6@huawei.com>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>