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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/
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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.