From DT_GNU_HASH parsing:

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/* Number of bitmask words is required to be power of 2 */
nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
obj->maskwords_bm_gnu = nmaskwords - 1;

...

obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
    obj->buckets_gnu != NULL;
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The nmw_power2 statement can be rewritten using the powerof2() macro from sys/param.h:

nmw_power2 = powerof2(nmaskwords);

And valid_hash_gnu should probably include '&& nmaskwords > 0' (see underflow in obj->maskwords_bm_gnu if nmaskwords is less than 1).

I may eventually get around to attaching a patch, but this isn't a priority for us (just something that came up reviewing a similar change to the kernel linker, which will end up on bugzilla sometime soon).