From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1DXzFq-0001EM-M2 for user-mode-linux-devel@lists.sourceforge.net; Tue, 17 May 2005 03:24:50 -0700 Received: from dgate1.fujitsu-siemens.com ([217.115.66.35]) by sc8-sf-mx1.sourceforge.net with esmtp (Exim 4.41) id 1DXzFo-0001Ma-Sc for user-mode-linux-devel@lists.sourceforge.net; Tue, 17 May 2005 03:24:50 -0700 Message-ID: <4289C66C.9000709@fujitsu-siemens.com> From: Bodo Stroesser MIME-Version: 1.0 Subject: Re: [uml-devel] Re: uml-general-protection-fault even more kludgy but mergeable References: <200505170005.43629.blaisorblade@yahoo.it> <20050517100317.GB20584@bytesex> In-Reply-To: <20050517100317.GB20584@bytesex> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Tue, 17 May 2005 12:24:44 +0200 To: Gerd Knorr Cc: Blaisorblade , Jeff Dike , user-mode-linux-devel@lists.sourceforge.net Gerd Knorr wrote: >>So, in practice, it's correct to call bad_segv() as done in the patch, but we >>miss some cases. Only this time I've verified this well enough that I feel we >>could merge your patch. However, I've not found any possible *realistic* >>source of general protection faults. Especially I didn't find what expected >>(i.e. I/O errors). > > > The case I trapped into was an attempt to access I/O ports of a > process running inside the uml. The uml kernel then tried to > handle that as page fault, which didn't work very well ... > > Gerd > Unfortunately, I can't find the previous mails about this. So, maybe I'm totally wrong. If so, please discard this mail. Gerd, did you see the problem in SKAS3 on i386? If so, it would be nice to see what happens in SKAS0. I saw similar problems regarding bad LDT-descriptors. Processes using a bad descriptor loop on page_fault. The real fix for this is to add trap_no to the info, that is read from host by PTRACE_FAULTINFO. With this info, UML can distinguish between real page faults and other SIGSEGVs. In SKAS0, UML already has the full info, as it retrieves the info from a sigcontext. Regards, Bodo ------------------------------------------------------- This SF.Net email is sponsored by Oracle Space Sweepstakes Want to be the first software developer in space? Enter now for the Oracle Space Sweepstakes! http://ads.osdn.com/?ad_id=7412&alloc_id=16344&op=click _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel