Re: [PATCH v1 0/7] Remove in-tree usage of MAP_DENYWRITE

On Sat, Aug 14, 2021 at 01:57:31AM +0000, Al Viro wrote:

On Fri, Aug 13, 2021 at 02:58:57PM -1000, Linus Torvalds wrote:

quoted

On Fri, Aug 13, 2021 at 2:54 PM Linus Torvalds
[off-list ref] wrote:

quoted

And nobody really complained when we weakened it, so maybe removing it
entirely might be acceptable.

I guess we could just try it and see... Worst comes to worst, we'll
have to put it back, but at least we'd know what crazy thing still
wants it..

Umm...  I'll need to go back and look through the thread, but I'm
fairly sure that there used to be suckers that did replacement of
binary that way (try to write, count on exclusion with execve while
it's being written to) instead of using rename.  Install scripts
of weird crap and stuff like that...

... and before anyone goes off - I certainly agree that using that
behaviour is not a good idea and had never been one.  All I'm saying
is that there at least used to be very random (and rarely exercised)
bits of userland relying upon that behaviour.