Re: Non-Exec stack patches

[John Reiser]

> Only one mprotect() call is needed to make the entire stack
> executable.

mprotect() only works on the portion that is currently allocated.
If the stack grows, then another call is needed.  Tracking the high-
water mark is an expense.  Forcing the allocation of the maximum
extent for the stack of the current thread, even to the same copy-
on-write all-zero page, can cause memory overcommit problems.

--
John Reiser, jreiser@xxxxxxxxxxxx

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