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Date: Thu, 25 Oct 2012 16:55:16 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Jonas Bonn <jonas@southpole.se>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] openrisc: move sys_clone's stack determination to
 copy_thread
Message-ID: <20121025155516.GL2616@ZenIV.linux.org.uk>
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 <1351179999-8376-2-git-send-email-jonas@southpole.se>
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On Thu, Oct 25, 2012 at 05:46:38PM +0200, Jonas Bonn wrote:
> Signed-off-by: Jonas Bonn <jonas@southpole.se>
> ---
>  arch/openrisc/kernel/process.c  |    6 +++++-
>  arch/openrisc/kernel/sys_or32.c |    8 +-------
>  2 files changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/openrisc/kernel/process.c b/arch/openrisc/kernel/process.c
> index e0874b8..efbe4f8 100644
> --- a/arch/openrisc/kernel/process.c
> +++ b/arch/openrisc/kernel/process.c
> @@ -170,7 +170,11 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
>  	} else {
>  		*userregs = *regs;
>  
> -		userregs->sp = usp;
> +		if (usp)
> +			userregs->sp = usp;		/* clone */

OK

> +		else
> +			userregs->sp = regs->sp;	/* fork/clone */

What for?  userregs->sp will be equal to regs->sp at that point, unless
your compiler is very badly broken.  You've copied *regs to *userregs
wholesale, just above that if...