>>> On 09.09.16 at 15:50, <konrad.w...@oracle.com> wrote: > On Fri, Sep 09, 2016 at 02:33:18PM +0100, Ross Lagerwall wrote: >> On 08/24/2016 03:22 AM, Konrad Rzeszutek Wilk wrote: >> > So that when we apply the patch again the .bss is cleared. >> > Otherwise we may find some variables containing old values. >> > >> > The payloads may contain various .bss - especially if -fdata-sections >> > is used which can create .bss.<name> sections. >> > >> >> After having thought about this again, I'm not sure it makes much sense. Any >> data sections in the payload are not reset to their initial values, so >> resetting the bss only may result in an unexpected combination of new & old >> data/bss. > > Regardless of that I think clearing the .bss upon applying the livepatch is > still the right thing to do. > > Regarding of the .data - we could have a copy of the .data the first time > we load - and then during application copy over it from the original one?. > >> >> Perhaps it just needs to be documented that a payload's bss/data is >> untouched across revert/apply? > > It really cuts down on bugs if we clear the .bss. It is kind of ingrained in > every > developer that the .bss is zero-ed out at startup.
I don't think Ross meant to suggest to not clear it at all: Clearing it at load time is the equivalent of loading actual data into initialized sections. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
