There's one flag that may need reservation: O_REGULAR, implemented by NetBSD and asked for in Linux in https://github.com/uapi-group/kernel-features

In D50703#1157920, @brooks wrote:

In D50703#1157830, @markj wrote:

Running out of O_* flag bits will be catastrophic

Why "catastrophic"? We could add an openat2() which takes more flags, like Linux did already. In any case, I do agree that we should be careful about adding new flags.

That might be a bit strong. I'll rephrase. My big worry is that POSIX/Linux add more useful flags and it becomes impossible for us to have source compatibility. I believe Linux has been a less liberal in allocating flag bits so they have a lot more room for growth which adds to the risk. Effectively having to deprecate open() would be a decade+ long project requiring cooperation between all POSIX projects and if we run out of O_ bits first we'll probably lose good will.

openat2 seems generally reasonable except for the bit the glibc doesn't provide bindings which will prove annoying with CHERI compartmentalization where we're not going to allow random code to use __syscall(2).

I wonder what we should do about github.com/freebsd/freebsd-src/pull/1698 then?

I have mixed feelings about it. On one hand it's in POSIX and it provides a certain symmetry. On the other hand, it sounds like Linux won't implement it so it probably shouldn't have been added to POSIX in the first place. I'm more worried about the recent addition of O_NAMEDATTR which is source compatible with nothing (apparently sort of Solaris O_XATTR).

In D45305#1035284, @kib wrote:

There is definitely a memory corruption issue, and from the report, it seems that panic is typically not triggered (immediately).

Now crashing like this:

Still crashes with this fix & commit b6f4a3fa75d24637b4d81035655fcb3d3ea187ad applied.

I can confirm the patch works as intended.

In D45175#1030482, @kib wrote:

In D45175#1030481, @rbranco_suse.com wrote:

The native FreeBSD ipcs command also uses these sysctl's.

So what is the problem with native?

In D45175#1030482, @kib wrote:

In D45175#1030481, @rbranco_suse.com wrote:

The native FreeBSD ipcs command also uses these sysctl's.

So what is the problem with native?

The native FreeBSD ipcs command also uses these sysctl's.

I opened a new version at: https://github.com/freebsd/freebsd-src/pull/1205

What is the failure on armv7?

The manpage states:

I successfully tested the patch on a QEMU VM.