Date:   Tue, 7 Dec 2021 12:10:21 -0500
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Kalesh Singh <kaleshsingh@google.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Ingo Molnar <mingo@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-fsdevel@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Yabin Cui <yabinc@google.com>
Subject: Re: [RFC][PATCH] tracefs: Set all files to the same group ownership
 as the mount option
Message-ID: <20211207121021.4d261d6e@gandalf.local.home>
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References: <20211206211219.3eff99c9@gandalf.local.home>
        <CAC_TJve8MMAv+H_NdLSJXZUSoxOEq2zB_pVaJ9p=7H6Bu3X76g@mail.gmail.com>
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On Tue, 7 Dec 2021 09:04:30 -0800
Kalesh Singh <kaleshsingh@google.com> wrote:

> One thing that I missed before: There are files that can be generated
> after the mount, for instance when a new synthetic event is added new
> entries for that event are created under events/synthetic/ and when a
> new instance is created the new entries generated under instances/.
> These new entries don't honor the gid specified when mounting. Could
> we make it so that they also respect the specified gid?

They don't?

/me looks at code

Aw crap. I thought since I have this:

static int tracefs_parse_options(char *data, struct tracefs_mount_opts *opts)
{
[..]
		case Opt_gid:
			if (match_int(&args[0], &option))
				return -EINVAL;
			gid = make_kgid(current_user_ns(), option);
			if (!gid_valid(gid))
				return -EINVAL;

			opts->gid = gid;

			set_gid(tracefs_mount->mnt_root, gid);
[..]


That the new files would inherit the opts->gid. But I see that they do not.

I'll add that as a separate patch.

Thanks for bringing that to my attention.

-- Steve