From: Linus Torvalds <torvalds@linux-foundation.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Felipe Contreras <felipe.contreras@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Linux 3.11-rc4
Date: Mon, 5 Aug 2013 10:39:15 -0700 [thread overview]
Message-ID: <CA+55aFy61PbNZda8f+42T9e7TioWd+W1s70UA6h+xnARjX3usA@mail.gmail.com> (raw)
In-Reply-To: <20130805132948.GA14942@redhat.com>
On Mon, Aug 5, 2013 at 6:29 AM, Oleg Nesterov <oleg@redhat.com> wrote:
>
> I never used wine, but I am puzzled anyway. This patch really looks
> like a simple and minor bugfix.
The patch is indeed trivial, but.. What's the locking here?
Afaik, ptrace_detach() by the parent can race with do_exit() by the
child, and they now _both_ do flush_ptrace_hw_breakpoint(). Or am I
wrong? We have that whole "get tasklist_lock for writing and then
check child->ptrace" logic there exactly due to that race, no?
That said, Felipe, can you double-check that it's not timing-related
in some subtle way, and test multiple times with just that commit
reverted (and not reverted) to make sure that it's 100% that one
single line by that particular commit? Because it does seem very
benign..
Linus
next prev parent reply other threads:[~2013-08-05 17:39 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-04 21:09 Linux 3.11-rc4 Linus Torvalds
2013-08-05 2:34 ` O_TMPFILE fs corruption (Re: Linux 3.11-rc4) Andy Lutomirski
2013-08-05 3:45 ` Linus Torvalds
2013-08-05 4:45 ` Andrew Lutomirski
2013-08-05 8:26 ` Christoph Hellwig
2013-08-05 16:04 ` Jörn Engel
2013-08-05 14:31 ` Al Viro
2013-08-05 4:20 ` Linux 3.11-rc4 Felipe Contreras
2013-08-05 13:29 ` Oleg Nesterov
2013-08-05 14:27 ` Felipe Contreras
2013-08-05 14:39 ` Oleg Nesterov
2013-08-05 17:02 ` Felipe Contreras
2013-08-05 17:11 ` Oleg Nesterov
2013-08-05 17:40 ` Felipe Contreras
2013-08-05 17:56 ` Oleg Nesterov
2013-08-05 17:39 ` Linus Torvalds [this message]
2013-08-05 17:43 ` Felipe Contreras
2013-08-05 18:08 ` Felipe Contreras
2013-08-05 17:47 ` Oleg Nesterov
2013-08-05 18:46 ` Oleg Nesterov
2013-08-05 18:54 ` Linus Torvalds
2013-08-05 18:57 ` Oleg Nesterov
2013-08-05 19:06 ` Linus Torvalds
2013-08-06 15:43 ` [PATCH 0/1] (Was: Linux 3.11-rc4) Oleg Nesterov
2013-08-06 15:43 ` [PATCH 1/1] Revert "ptrace: PTRACE_DETACH should do flush_ptrace_hw_breakpoint(child)" Oleg Nesterov
2013-08-07 12:05 ` [PATCH 0/1] (Was: Linux 3.11-rc4) Grazvydas Ignotas
2013-08-07 17:22 ` Oleg Nesterov
2013-08-07 19:26 ` Linus Torvalds
2013-08-07 19:27 ` Oleg Nesterov
2013-08-07 19:47 ` Linus Torvalds
2013-08-08 15:41 ` Oleg Nesterov
2013-08-08 16:25 ` Linus Torvalds
2013-08-08 16:54 ` Frederic Weisbecker
2013-08-08 18:15 ` Oleg Nesterov
2013-08-09 16:45 ` Frederic Weisbecker
2013-08-09 17:12 ` Oleg Nesterov
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