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Date: Wed, 1 Apr 2009 17:21:22 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
Subject: Re: do_execve() needs const qualifiers (was Re: [patch 3/3] uml:
	fix warnings in kernel_execve)
Message-ID: <20090401162122.GE28946@ZenIV.linux.org.uk>
References: <E1LoMQ2-0007bB-By@pomaz-ex.szeredi.hu> <E1LoMTw-0007d2-AI@pomaz-ex.szeredi.hu> <20090401161114.GF3848@hack>
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Sender: linux-kernel-owner@vger.kernel.org
To: Am??rico Wang <xiyou.wangcong@gmail.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>, user-mode-linux-devel@lists.sourceforge.net, jdike@addtoit.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org
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On Thu, Apr 02, 2009 at 12:11:14AM +0800, Am??rico Wang wrote:
> On Mon, Mar 30, 2009 at 08:45:12PM +0200, Miklos Szeredi wrote:
> >From: Miklos Szeredi <mszeredi@suse.cz>
> >
> >Fix the following warnings:
> >
> >arch/um/kernel/syscall.c: In function 'kernel_execve':
> >arch/um/kernel/syscall.c:130: warning: passing argument 1 of 'um_execve' discards qualifiers from pointer target type
> >arch/um/kernel/syscall.c:130: warning: passing argument 2 of 'um_execve' discards qualifiers from pointer target type
> >arch/um/kernel/syscall.c:130: warning: passing argument 3 of 'um_execve' discards qualifiers from pointer target type
> >
> >Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
> >---
> > arch/um/kernel/syscall.c |    3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> >Index: linux-2.6/arch/um/kernel/syscall.c
> >===================================================================
> >--- linux-2.6.orig/arch/um/kernel/syscall.c	2009-03-30 20:25:17.000000000 +0200
> >+++ linux-2.6/arch/um/kernel/syscall.c	2009-03-30 20:36:20.000000000 +0200
> >@@ -127,7 +127,8 @@ int kernel_execve(const char *filename,
> > 
> > 	fs = get_fs();
> > 	set_fs(KERNEL_DS);
> >-	ret = um_execve(filename, argv, envp);
> >+	ret = um_execve((char *)filename, (char __user *__user *)argv,
> >+			(char __user *__user *) envp);
> 
> Well... I found this many days ago and I did a similar fix.
> 
> However, I think this doesn't fix the real problem. The real problem
> is do_execve() doesn't have the correct const qualifiers, I am queueing
> a huge patch to fix all the 'const' issues from do_execve() and more,
> but I don't if Al would like it or not.

I don't know...  The thing is, it'll trail down into bprm->filename /
bprm->interp and the things get very ugly very fast from that point.