Tested on x86_64. build-many-glibcs run in progress.
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Ensure the following properties of chunks encountered during binning:
- victim chunk has reasonable size
- next chunk has reasonable size
- next->prev_size == victim->size
- valid double linked list
- PREV_INUSE of next chunk is unset

    * malloc/malloc.c (_int_malloc): Additional binning code checks.

(cherry picked from commit b90ddd08f6dd688e651df9ee89ca3a69ff88cd0c)
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 malloc/malloc.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

-- 
Cheers,
Carlos.