On 5/11/23 07:08, Zack Weinberg wrote:
Unless someone knows of a bug in some old kernel where the first*disk block* of an oversized mmap would be properly zeroed and then the rest of it would be memory garbage
Yes, that was the reason I went back to configuring a getpagesize substitute: I wanted the test to continue to check for that improperly-zeroed bug (a check that I didn't notice in my earlier commit).
Although the original motivation for the improperly-zeroed test is old GNU grep, GNU grep no longer uses mmap. However, perhaps some other package now cares about this behavior, so it's probably better to keep testing for it.