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Re: Memory corruption problem

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On 16 Nov in article <dd0dec5757.Alan.Adams@ArmX6.adamshome.org.uk>,
   Alan Adams <alan@adamshome.org.uk> wrote:
> In message <5757e90ea1News03@avisoft.f9.co.uk>
>           Martin <News03@avisoft.f9.co.uk> wrote:
> > On 16 Nov in article <2e86dd5757.Alan.Adams@ArmX6.adamshome.org.uk>,
> >    Alan Adams <alan@adamshome.org.uk> wrote:

[Snip]

> > However, if you use indirection operators !?$ it is possible that
> > something that *should* be within your wimpslot is not. It is
> > possible to validate write addresses?

> There are a huge number of indirection operaions, not least among
> the ring buffers used in the network communications. My suspicion
> is that somewhere among them a completely invalid address is being
> produced.

> > If your applications use memory that is outside your slot
> > (probably RMA?) then overrunning a block, or writing to the wrong
> > address, can have predictable unpredictable results. Again, is it
> > possible to validate writes?

> I'm not using RMA

Where is the memory you *should* be using?
Are you using lots of individually allocated blocks?
Or are you using your own Heap to manage blocks?

If there are a multiplicity of writes that cannot be verified, can
you add a guard word at the end of each block, and check they are
valid as often as possible?

> I'm wondering whether a high-vector build would help. If the disk
> and socket data areas are protected, it would catch such invalid
> writes. I'm on an ARMX6, and I don't know immediately whether
> there is a high-vector build available. I seem to recall that
> there is.

Not sure if one is available ... but anyway, the HV build only
protects what was in 'Zero page' which probably excludes disk &
socket areas.

-- 
Martin Avison 
Note that unfortunately this email address will become invalid
without notice if (when) any spam is received. 

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Thread

Memory corruption problem Alan Adams <alan@adamshome.org.uk> - 2018-11-16 13:15 +0000
  Re: Memory corruption problem Martin <News03@avisoft.f9.co.uk> - 2018-11-16 15:21 +0000
    Re: Memory corruption problem Alan Adams <alan@adamshome.org.uk> - 2018-11-16 15:53 +0000
      Re: Memory corruption problem Martin <News03@avisoft.f9.co.uk> - 2018-11-16 20:04 +0000
        Re: Memory corruption problem Alan Adams <alan@adamshome.org.uk> - 2018-11-16 22:38 +0000
          Re: Memory corruption problem Martin <News03@avisoft.f9.co.uk> - 2018-11-16 23:46 +0000
  Re: Memory corruption problem David Buck <dbuckhome@gmail.com> - 2018-11-16 23:15 -0800
    Re: Memory corruption problem Alan Adams <alan@adamshome.org.uk> - 2018-11-17 12:21 +0000
      Re: Memory corruption problem Alan Adams <alan@adamshome.org.uk> - 2018-11-17 13:10 +0000
        Re: Memory corruption problem Martin <News03@avisoft.f9.co.uk> - 2018-11-17 19:01 +0000
          Re: Memory corruption problem Alan Adams <alan@adamshome.org.uk> - 2018-11-17 21:04 +0000
        Re: Memory corruption problem Erik G <noreply123@xs4all.nl> - 2018-11-24 20:17 +0100
    Re: Memory corruption problem "John Williams (News)" <UCEbin@tiscali.co.uk> - 2018-11-17 12:26 +0000
    Re: Memory corruption problem David Higton <dave@davehigton.me.uk> - 2018-11-17 20:59 +0000

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