Re: [PATCH 09/15] clone.2: ERRORS: Add EACCESS with CLONE_INTO_CGROUP + clone3

On Sat, Sep 11, 2021 at 12:47:10AM +0200, Alejandro Colomar wrote:

[Andrew]:
I noticed that clone3 can send the EACCES errno after I wrote a
program that used clone3 with the CLONE_INTO_CGROUP flag.
To me, it's important to know what kind of failure occurred if the
clone3() fails, so I was glad that a unique errno is set for
this case, but it wasn't documented on the clone man page.

[Christian]:

Hey Alejandro,

I was on vacation last week so just catching up with mails now.

In essence, any error that could occur during regular fs-based migration
at write-time can also occur during CLONE_INTO_CGROUP. The clone3()
manpage just has the inverse of that above statement:

"Note that all of the usual restrictions (described in cgroups(7)) on
placing a process into a version 2 cgroup apply."

Reported-by: Andrew Wock <redacted>
Acked-by: Christian Brauner <redacted>
Signed-off-by: Alejandro Colomar <redacted>
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Thanks for picking that up.
Christian