> I think it's unlikely that you've got 64K distinct .so files that
> you've ever mmaped into an executable.

I agree.  Until approximately now, it was not clear to me that this
checsumming sil^Wthing applied only to .so files.

> (I saw no suggestion that cache info for libraries that have gone MIA
> would be retained, and nobody else's system does this AFAICT; I just
> looked at several).

I saw no mechanism to get rid of outdated cache info mentioned.
Pehraps this was in the same message I didn't see that made it clear
this applied to just .so files....

> From a pragmatic point of view, it seems reasonable to use both a
> 32-bit CRC and a 32-bit sum computed using a completely different
> method, plus the metadata.  We can't _really_ say how often there
> will be collisions, but I'd bet you an awful lot of money that you
> won't see one this decade.

I wouldn't go that far.  Depending on the consequences of a collision,
we have to also consider the possibility of someone deliberately trying
to construct a file so as to collide, in which case a whole lot of
things change.  CRCs are useless under such circumstances, for example.

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