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.