Fix GC heap corruption on ARM #1389
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The allocate_in_free code path in allocate_in_expanded_heap incorrectly calculated the large (double) alignment padding size when limiting the plug size (SHORT_PLUGS) if set_padding_on_saved_p was true:
set_padding_in_expand (old_loc, set_padding_on_saved_p, pinned_plug_entry); // Sets the padding flag on the saved plug
...
pad += switch_alignment_size (is_plug_padded (old_loc)); // Reads the padding flag from the old (different!) plug
That caused access violation during a later heap walk since the g_gc_pFreeObjectMethodTable pointer marking the gap was not placed at the right address.
Maoni0
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The
allocate_in_freecode path in theallocate_in_expanded_heapfunction would incorrectly calculate the large (double) alignment padding size when limiting the plug size (SHORT_PLUGS) ifset_padding_on_saved_pwastrue:That caused access violation during a later heap walk since the
g_gc_pFreeObjectMethodTablepointer marking the gap was not placed at the right address.