Re: [PATCH] mm: get_cmdline use arg_lock instead of mmap_sem

From: Michal Koutný
Date: Wed Apr 17 2019 - 10:41:47 EST

On Wed, Apr 17, 2019 at 03:41:52PM +0200, Michal Hocko <mhocko@xxxxxxxxxx> 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].