Re: [PATCH] nommu arch dont zero the anonymous mapping by adding UNINITIALIZE flag

[David Howells]

Aubrey Li <aubreylee@xxxxxxxxx> wrote:

> malloc() allocates size bytes and returns a pointer to the allocated memory.
> ****The memory is not cleared.****

But this is *not* malloc().  It's mmap().  Are you prepared to guarantee that
there are no applications out there that don't rely on anon mmap() giving
zeroed memory?

The MMU-mode clearing is done for security reasons - there shouldn't be any
leakage between processes, and because the zero page can just be faulted in.

Personally, I'd prefer to maintain compatibility with MMU-mode wherever
possible, but I'm happy with overrides like the MAP_UNINITIALISED flag
suggested.

David
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