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Date:   Wed, 17 Apr 2019 16:41:42 +0200
From:   Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>
To:     Michal Hocko <mhocko@kernel.org>
Cc:     Bartosz Golaszewski <brgl@bgdev.pl>,
        Arun KS <arunks@codeaurora.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Mateusz Guzik <mguzik@redhat.com>,
        Vlastimil Babka <vbabka@suse.cz>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: get_cmdline use arg_lock instead of mmap_sem
Message-ID: <20190417144142.GF8962@blackbody.suse.cz>
References: <20190417120347.15397-1-mkoutny@suse.com>
 <20190417134152.GM5878@dhcp22.suse.cz>
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On Wed, Apr 17, 2019 at 03:41:52PM +0200, Michal Hocko <mhocko@kernel.org> wrote:
> Don't we need to use the lock in prctl_set_mm as well then?

Correct. The patch alone just moves the race from
get_cmdline/prctl_set_mm_map to get_cmdline/prctl_set_mm.

arg_lock could be used in prctl_set_mm but the better idea (IMO) is
complete removal of that code in favor of prctl_set_mm_map [1].

Michal

[1] https://lore.kernel.org/lkml/20180405182651.GM15783@uranus.lan/