Re: [LTP] ltp_clone alignment issues.

Carmelo AMOROSO
2010-09-29T13:35:18Z

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On 9/27/2010 3:34 PM, Carmelo AMOROSO wrote:
> Folks,
> I want to reopen an old discussion on ltp_clone and stack alignment
> issue (see
> http://sourceforge.net/mailarchive/message.php?msg_name=4B421480.1040400%40petalogix.com).
> Indeed recently a commit has partially fixed a problem on ARM
> (0056e395170eb8fc3ffbb22d7bd364fe47c2013e), but I think this should be
> extended to all archs that have stack that grows downwards.
>
> Indeed, as Jiri replied in that old thread, the value passed to clone as
> child stack should be never accessed, because it is the topmost address
> of the memory allocated for the child process (it's the previous stack
> pointer).
>
> So, in archs that do not like unaligned stack, using (stack - size - 1 )
> will cause the process to be killed by a SIGBUS, on other archs, we are
> just wasting one byte of the malloc-ed stack.
>
> On my SH4 arch, the stack must be 4byte aligned (as in ARM).
>
> Please, find attached a patch against master branch
>
> Best regards,
> Carmelo

Hi,
any feedback on this ?

Cheers,
Carmelo
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