Re: directory sticky bit strangeness following libc6 update

On Sun, Apr 19, 2020 at 01:01:17AM +0200, Matthias Ferdinand wrote:
> On Sat, Apr 18, 2020 at 07:48:27AM -0500, Bob Tracy wrote:
> > > If the rules had changed, it should not succeed even without
> > > O_CREAT. A bug?
> > 
> > That's *my* take on the matter.  It will be a day or so before I can
> > check upstream and see if any bug reports have been opened against
> > libc6, but if someone else would care to look in the meantime :-) ...
> 
> found https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=954230, added
> O_CREAT information to it.
> 
> Matthias Ferdinand

An update to that bug report suggested checking
/proc/sys/fs/protected_regular, which is now set to 2 by default on my
alpha.  No idea where the new setting is coming from.  It's a sysctl
setting that has evidently been around for a good while.  Other systems
I have access to that are running the same kernel have that value set
to 0.  So I guess the current verdict is, "works as documented".  Would
still like to know what changed, because it's not being touched by the
kernel build process: else, the other systems running the same kernel
would be exhibiting the same behavior.

--Bob