From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Sun, 09 Feb 2003 08:48:40 +0000 Subject: Re: [Linux-ia64] sigaltstack and RBS 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 Sun, 9 Feb 2003 18:58:06 +1100, Matt Chapman said: Matt> Here's a small test program. Hmmh, the test program doesn't test backing-store _overflow_, it tests what happens when you _remove_ a formerly valid mapping. The program fails because the "rfi" that gets executed when returning from mprotect() may end up trying to restore registers that got spilled to the backing store before the call mprotect(), the mprotect() then removes access permission and hence the "rfi" can never finish execution (effectively, the mprotect() makes the contents of the spilled stacked registers disappear for good). The current sigaltstack implementation isn't designed to handle such a case. And I'm not sure whether it should. Is there a particular reason you want to do this sort of thing? --david