linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: chenqiwu <qiwuchen55@gmail.com>,
	christian.brauner@ubuntu.com, mingo@kernel.org,
	kernel-team@android.com, linux-kernel@vger.kernel.org,
	chenqiwu@xiaomi.com
Subject: Re: [PATCH v2] kernel/exit: do panic earlier to get coredump if global init task exit
Date: Tue, 17 Dec 2019 20:33:15 +0100	[thread overview]
Message-ID: <20191217193315.GG2844@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20191217152333.GC23152@redhat.com>

On Tue, Dec 17, 2019 at 04:23:33PM +0100, Oleg Nesterov wrote:
> On 12/17, chenqiwu wrote:
> >
> > But in fact, I think atomic_read()
> > can avoid the racy even if both threads exit in parallel, since it is
> > an atomic operation forever.
> 
> Hmm, not sure I understand. atomic_read() is just READ_ONCE(), it can't be
> re-ordered but that is all.

That, atomic_read() is just a read. It doesn't modify the variable,
therefore there isn't anything 'atomic' even remotely possible.

  reply	other threads:[~2019-12-17 19:33 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-16  3:18 [PATCH v2] kernel/exit: do panic earlier to get coredump if global init task exit qiwuchen55
2019-12-16 10:27 ` Christian Brauner
2019-12-16 17:28 ` Oleg Nesterov
2019-12-16 17:44   ` Christian Brauner
2019-12-17 10:50     ` chenqiwu
2019-12-17 14:25       ` Oleg Nesterov
2019-12-17 14:56         ` chenqiwu
2019-12-17 15:23           ` Oleg Nesterov
2019-12-17 19:33             ` Peter Zijlstra [this message]
2019-12-18  8:08             ` chenqiwu
2019-12-17 14:14     ` Oleg Nesterov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191217193315.GG2844@hirez.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=chenqiwu@xiaomi.com \
    --cc=christian.brauner@ubuntu.com \
    --cc=kernel-team@android.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@kernel.org \
    --cc=oleg@redhat.com \
    --cc=qiwuchen55@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).