Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Thu, 25 Mar 2021 21:40:15 +0100
From:   Oleg Nesterov <oleg@redhat.com>
To:     "Eric W. Biederman" <ebiederm@xmission.com>
Cc:     Jens Axboe <axboe@kernel.dk>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        io-uring <io-uring@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Stefan Metzmacher <metze@samba.org>
Subject: Re: [PATCH 0/2] Don't show PF_IO_WORKER in /proc/<pid>/task/
Message-ID: <20210325204014.GD28349@redhat.com>
References: <20210325164343.807498-1-axboe@kernel.dk>
 <m1ft0j3u5k.fsf@fess.ebiederm.org>
 <CAHk-=wjOXiEAjGLbn2mWRsxqpAYUPcwCj2x5WgEAh=gj+o0t4Q@mail.gmail.com>
 <CAHk-=wg1XpX=iAv=1HCUReMbEgeN5UogZ4_tbi+ehaHZG6d==g@mail.gmail.com>
 <3a1c02a5-db6d-e3e1-6ff5-69dd7cd61258@kernel.dk>
 <m1zgyr2ddh.fsf@fess.ebiederm.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <m1zgyr2ddh.fsf@fess.ebiederm.org>
User-Agent: Mutt/1.5.24 (2015-08-30)
Precedence: bulk

On 03/25, Eric W. Biederman wrote:
>
> So looking quickly the flip side of the coin is gdb (and other
> debuggers) needs a way to know these threads are special, so it can know
> not to attach.

may be,

> I suspect getting -EPERM (or possibly a different error code) when
> attempting attach is the right was to know that a thread is not
> available to be debugged.

may be.

But I don't think we can blame gdb. The kernel changed the rules, and this
broke gdb. IOW, I don't agree this is gdb bug.

Oleg.