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    SubjectRe: [v6 PATCH 07/21] x86/insn-eval: Add utility function to get segment descriptor
    On Wed, Apr 26, 2017 at 02:51:56PM -0700, Ricardo Neri wrote:
    > > > + seg >= current->active_mm->context.ldt->size)) {
    > >
    > > ldt->size is the size of the descriptor table but you've shifted seg by
    > > 3. That selector index is shifted by 3 (to the left) to form an offset
    > > into the descriptor table because the entries there are 8 bytes.
    >
    > I double-checked the ldt code and it seems to me that size refers to the
    > number of entries in the table; it is always multiplied by
    > LDT_ENTRY_SIZE [1], [2]. Am I missing something?

    No, you're not. I fell into that wrongly named struct member trap.

    So ldt_struct.size should actually be called ldt_struct.n_entries or
    similar. Because what's in there is now is not "size".

    And then code like

    new_ldt->size * LDT_ENTRY_SIZE

    would make much more sense if written like this:

    new_ldt->n_entries * LDT_ENTRY_SIZE

    Would you fix that in a prepatch pls?

    Thanks.

    --
    Regards/Gruss,
    Boris.

    SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
    --

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