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Re: [PATCH] proc: revert /proc/<pid>/maps [stack:TID] annotation

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On 20 January 2016 at 05:00, Kirill A. Shutemov <kirill@shutemov.name> wrote:
> I doubt it can be very useful as it's unreliable: if two stacks are
> allocated end-to-end (which is not good idea, but still) it can only
> report [stack:XXX] for the first one as they are merged into one VMA.
> Any other anon VMA merged with the stack will be also claimed as stack,
> which is not always correct.

It is quite uncommon because you will always have an intervening guard
page that separates the two stack vmas.  To have the vmas merge, you
will have to disable guard pages which is an even worse idea.

A more relevant argument about its unreliability is context changes
due to makecontext/setcontext, which could momentarily show the heap
or some other arbitrary vma as a stack.

Siddhesh
-- 
http://siddhesh.in

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[PATCH] proc: revert /proc/<pid>/maps [stack:TID] annotation Johannes Weiner <hannes@cmpxchg.org> - 2016-01-19 19:10 +0100
  Re: [PATCH] proc: revert /proc/<pid>/maps [stack:TID] annotation Andrew Morton <akpm@linux-foundation.org> - 2016-01-19 23:20 +0100
    Re: [PATCH] proc: revert /proc/<pid>/maps [stack:TID] annotation Johannes Weiner <hannes@cmpxchg.org> - 2016-01-20 00:40 +0100
    Re: [PATCH] proc: revert /proc/<pid>/maps [stack:TID] annotation "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-01-20 00:40 +0100
      Re: [PATCH] proc: revert /proc/<pid>/maps [stack:TID] annotation Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com> - 2016-01-20 04:30 +0100
    Re: [PATCH] proc: revert /proc/<pid>/maps [stack:TID] annotation Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com> - 2016-01-20 04:20 +0100
      Re: [PATCH] proc: revert /proc/<pid>/maps [stack:TID] annotation Andrew Morton <akpm@linux-foundation.org> - 2016-01-20 06:30 +0100
  [PATCH] proc: add missing 'mm' variable in nommu is_stack() Arnd Bergmann <arnd@arndb.de> - 2016-01-21 12:00 +0100

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