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From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: "Michal Koutný" <mkoutny@suse.com>,
	akpm@linux-foundation.org, arunks@codeaurora.org, brgl@bgdev.pl,
	geert+renesas@glider.be, ldufour@linux.ibm.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	mguzik@redhat.com, mhocko@kernel.org, rppt@linux.ibm.com,
	vbabka@suse.cz
Subject: Re: [PATCH 1/3] mm: get_cmdline use arg_lock instead of mmap_sem
Date: Tue, 30 Apr 2019 13:45:17 +0300	[thread overview]
Message-ID: <20190430104517.GF2673@uranus.lan> (raw)
In-Reply-To: <1a7265fa-610b-1f2a-e55f-b3a307a39bf2@virtuozzo.com>

On Tue, Apr 30, 2019 at 12:53:51PM +0300, Kirill Tkhai wrote:
> > 
> > Well, strictly speaking we probably should but you know setup of
> > the @arg_start by kernel's elf loader doesn't cause any side
> > effects as far as I can tell (its been working this lockless
> > way for years, mmap_sem is taken later in the loader code).
> > Though for consistency sake we probably should set it up
> > under the spinlock.
> 
> Ok, so elf loader doesn't change these parameters.
> Thanks for the explanation.

It setups these parameters unconditionally. I need to revisit
this moment. Technically (if only I'm not missing something
obvious) we might have a race here with prctl setting up new
params, but this should be harmless since most of them (except
stack setup) are purely informative data.

  reply	other threads:[~2019-04-30 10:45 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-17 12:03 [PATCH] mm: get_cmdline use arg_lock instead of mmap_sem Michal Koutný
2019-04-17 13:41 ` Michal Hocko
2019-04-17 14:41   ` Michal Koutný
2019-04-17 14:55     ` Michal Hocko
2019-04-18 13:50       ` [PATCH] prctl_set_mm: downgrade mmap_sem to read lock Michal Koutný
2019-04-18 14:09         ` Cyrill Gorcunov
2019-04-18 14:15         ` Michal Hocko
2019-04-18 14:27         ` Laurent Dufour
2019-04-18 18:23         ` Cyrill Gorcunov
2019-04-30  8:18           ` [PATCH 0/3] Reduce mmap_sem usage for args manipulation Michal Koutný
2019-04-30  8:18             ` [PATCH 1/3] mm: get_cmdline use arg_lock instead of mmap_sem Michal Koutný
2019-04-30  9:09               ` Kirill Tkhai
2019-04-30  9:38                 ` Cyrill Gorcunov
2019-04-30  9:53                   ` Kirill Tkhai
2019-04-30 10:45                     ` Cyrill Gorcunov [this message]
2019-04-30 10:56                       ` Michal Koutný
2019-04-30 13:24                         ` Cyrill Gorcunov
2019-04-30  8:18             ` [PATCH 2/3] prctl_set_mm: Refactor checks from validate_prctl_map Michal Koutný
2019-04-30  9:27               ` Kirill Tkhai
2019-04-30  8:18             ` [PATCH 3/3] prctl_set_mm: downgrade mmap_sem to read lock Michal Koutný
2019-04-30  8:55               ` Kirill Tkhai
2019-04-30  9:08                 ` Cyrill Gorcunov
2019-04-30  9:11                   ` Kirill Tkhai
2019-05-02 12:52                     ` [PATCH v3 0/2] Reduce mmap_sem usage for args manipulation Michal Koutný
2019-05-02 12:52                       ` [PATCH v3 1/2] prctl_set_mm: Refactor checks from validate_prctl_map Michal Koutný
2019-05-02 20:57                         ` Cyrill Gorcunov
2019-05-02 12:52                       ` [PATCH v3 2/2] prctl_set_mm: downgrade mmap_sem to read lock Michal Koutný
2019-05-02 20:57                         ` Cyrill Gorcunov
2019-05-06  9:28                         ` Kirill Tkhai
2019-05-07 17:42                         ` Michal Hocko

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