Re: [PATCH 2/3] tools/vm/page-types: suppress gcc warnings

From	David Rientjes <rientjes@google.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/3] tools/vm/page-types: suppress gcc warnings
Date	2015-11-12 06:50 +0100
Message-ID	<qtSVH-4P2-1@gated-at.bofh.it> (permalink)
References	<qthjr-5Fv-3@gated-at.bofh.it> <qthjs-5Fv-13@gated-at.bofh.it> <qtKv8-7HI-11@gated-at.bofh.it> <qtOp4-1Nx-19@gated-at.bofh.it>
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On Thu, 12 Nov 2015, Sergey Senozhatsky wrote:

> > This can't possibly be correct, the warnings are legitimate and the result
> > of the sigsetjmp() in the function.  You may be interested in
> > returns_twice rather than marking random automatic variables as volatile.
> 
> Hm, ok. I saw no probs with `int first' and `end' being volatile
> 

This will only happen with the undocumented change in your first patch 
which adds -O2.

I don't know what version of gcc you're using, but only "first" and "end" 
being marked volatile isn't sufficient since mere code inspection would 
show that "off" will also be clobbered -- it's part of the loop.
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Thread

[PATCH 0/3] tools/vm: trivial fixes Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2015-11-10 14:40 +0100
  [PATCH 2/3] tools/vm/page-types: suppress gcc warnings Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2015-11-10 14:40 +0100
    Re: [PATCH 2/3] tools/vm/page-types: suppress gcc warnings David Rientjes <rientjes@google.com> - 2015-11-11 21:50 +0100
      Re: [PATCH 2/3] tools/vm/page-types: suppress gcc warnings Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-11-12 02:00 +0100
        Re: [PATCH 2/3] tools/vm/page-types: suppress gcc warnings David Rientjes <rientjes@google.com> - 2015-11-12 06:50 +0100
  [PATCH 3/3] tools/vm/slabinfo: update struct slabinfo members' types Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2015-11-10 14:40 +0100
    Re: [PATCH 3/3] tools/vm/slabinfo: update struct slabinfo members'  types Christoph Lameter <cl@linux.com> - 2015-11-10 16:30 +0100
    Re: [PATCH 3/3] tools/vm/slabinfo: update struct slabinfo members'  types David Rientjes <rientjes@google.com> - 2015-11-11 22:00 +0100
      Re: [PATCH 3/3] tools/vm/slabinfo: update struct slabinfo members'  types Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-11-12 02:20 +0100
        Re: [PATCH 3/3] tools/vm/slabinfo: update struct slabinfo members'  types David Rientjes <rientjes@google.com> - 2015-11-12 06:10 +0100
          Re: [PATCH 3/3] tools/vm/slabinfo: update struct slabinfo members'  types Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-11-12 07:20 +0100
            Re: [PATCH 3/3] tools/vm/slabinfo: update struct slabinfo members'  types David Rientjes <rientjes@google.com> - 2015-11-12 11:00 +0100
  [PATCH 1/3] tools/vm: fix Makefile multi-targets Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2015-11-10 14:40 +0100
    Re: [PATCH 1/3] tools/vm: fix Makefile multi-targets Christoph Lameter <cl@linux.com> - 2015-11-10 16:30 +0100
    Re: [PATCH 1/3] tools/vm: fix Makefile multi-targets Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2015-11-11 13:30 +0100
      Re: [PATCH 1/3] tools/vm: fix Makefile multi-targets David Rientjes <rientjes@google.com> - 2015-11-11 21:40 +0100
        Re: [PATCH 1/3] tools/vm: fix Makefile multi-targets Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2015-11-12 02:00 +0100

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