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Re: [patch] mm, oom: remove task_lock protecting comm printing

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On Tue, Sep 22, 2015 at 04:30:13PM -0700, David Rientjes wrote:
> The oom killer takes task_lock() in a couple of places solely to protect
> printing the task's comm.
> 
> A process's comm, including current's comm, may change due to
> /proc/pid/comm or PR_SET_NAME.
> 
> The comm will always be NULL-terminated, so the worst race scenario would
> only be during update.  We can tolerate a comm being printed that is in
> the middle of an update to avoid taking the lock.
> 
> Other locations in the kernel have already dropped task_lock() when
> printing comm, so this is consistent.
> 
> Suggested-by: Oleg Nesterov <oleg@redhat.com>
> Signed-off-by: David Rientjes <rientjes@google.com>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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[patch] mm, oom: remove task_lock protecting comm printing David Rientjes <rientjes@google.com> - 2015-09-23 01:40 +0200
  Re: [patch] mm, oom: remove task_lock protecting comm printing Michal Hocko <mhocko@kernel.org> - 2015-09-23 09:50 +0200
  Re: [patch] mm, oom: remove task_lock protecting comm printing Vladimir Davydov <vdavydov@parallels.com> - 2015-09-23 10:10 +0200
    Re: [patch] mm, oom: remove task_lock protecting comm printing Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-09-23 11:20 +0200
      Re: [patch] mm, oom: remove task_lock protecting comm printing Vladimir Davydov <vdavydov@parallels.com> - 2015-09-23 11:40 +0200
        Re: [patch] mm, oom: remove task_lock protecting comm printing Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-09-23 11:50 +0200
          Re: [patch] mm, oom: remove task_lock protecting comm printing Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-09-23 12:00 +0200
          Re: [patch] mm, oom: remove task_lock protecting comm printing Vladimir Davydov <vdavydov@parallels.com> - 2015-09-23 12:10 +0200
            Re: [patch] mm, oom: remove task_lock protecting comm printing Michal Hocko <mhocko@kernel.org> - 2015-09-23 12:50 +0200
        Re: [patch] mm, oom: remove task_lock protecting comm printing Michal Hocko <mhocko@kernel.org> - 2015-09-23 11:50 +0200
  Re: [patch] mm, oom: remove task_lock protecting comm printing Johannes Weiner <hannes@cmpxchg.org> - 2015-09-24 21:50 +0200

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