Re: [PATCH 0/5] (Was: procfs: silence lockdep warning about read vs. exec seq_file)

From: Cyrill Gorcunov
Date: Mon Aug 04 2014 - 02:59:58 EST


On Sun, Aug 03, 2014 at 11:18:43PM +0200, Oleg Nesterov wrote:
> On 08/03, Oleg Nesterov wrote:
> >
> > The question is, why m_start() calls mm_access(). This is not even
> > strictly correct if the task execs between m_stop() + m_start().
> >
> > Can't we do something like below? The patch is obviously horrible and
> > incomplete, just to explain what I meant. Basically this is what
> > proc_mem_operations does.
>
> Absolutely untested, only for review.
>
> What do you all think?
>
> Sure, with this change you can't open (say) /proc/pid/maps, and read the
> new mappings after exec. But hopefully this is fine? And again, this
> matches /proc/pid/mem.
>
> lock_trace() users need another fix.

If only I didn't miss something obvious this is quite the good cleanup,
thanks Oleg!
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