From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Bligh Subject: Re: kernel panic in skb_copy_bits Date: Mon, 01 Jul 2013 09:29:02 +0100 Message-ID: References: <51CBAA48.3080802@oracle.com> <1372311118.3301.214.camel@edumazet-glaptop> <51CD0E67.4000008@oracle.com> <6BFD5AF235F72F13CE646A0D@nimrod.local> <51D0F514.3070309@oracle.com> Reply-To: Alex Bligh Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: Eric Dumazet , Frank Blaschka , "David S. Miller" , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, zheng.x.li@oracle.com, Xen Devel , Ian Campbell , Jan Beulich , Stefano Stabellini , Alex Bligh To: Joe Jin Return-path: In-Reply-To: <51D0F514.3070309@oracle.com> Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Joe, > Do you know if have a fix for above? so far we also suspected the > grant page be unmapped earlier, we using 4.1 stable during our test. A true fix? No, but I posted a patch set (see later email message for a link) that you could forward port. The workaround is: >> A workaround is to turn off O_DIRECT use by Xen as that ensures >> the pages are copied. Xen 4.3 does this by default. >> >> I believe fixes for this are in 4.3 and 4.2.2 if using the >> qemu upstream DM. Note these aren't real fixes, just a workaround >> of a kernel bug. > > The guest is pvm, and disk model is xvbd, guest config file as below: ... > I think this only for pvhvm/hvm? I don't have much experience outside pvhvm/hvm, but I believe it should work for any device. Testing was simple - just find all (*) the references to O_DIRECT in your device model and remove them! (*)=you could be less lazy than me and find the right ones. I am guessing it will be the same ones though. -- Alex Bligh