From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Mon, 07 Jul 2003 21:13:12 +0000 Subject: Re: copy_thread preserves kernel stack Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org >>>>> On Thu, 03 Jul 2003 12:02:54 +1000, Keith Owens said: Keith> ia64 has a comment "Note: if we get called through Keith> kernel_thread() then the memory above "(highest addr)" is Keith> valid kernel stack memory that needs to be copied as well". Keith> i386 kernel threads work fine without the extra stack Keith> wastage, so there is no generic reason to save the parent Keith> backtrace. Apart from unwind problems, I can see no reason Keith> for ia64 to preserve the parent's task in kernel threads. Keith> Any objections to me doing a patch that constructs an empty Keith> stack for ia64 kernel threads? If the patch is clean, I wouldn't have a problem with it. (Please make sure that the call-chain of the child thread is properly terminated, so the unwinder knows when to stop.) (There used to be only few kernel threads, with little risk of kernel stack overflows, but nowadays (2.5.xx) the situation is quite different, so it probably makes sense to make this change). --david