On Wed, Mar 18, 2015 at 07:25:22PM +0100, Oleg Nesterov wrote: > On 03/18, Cyrill Gorcunov wrote: > > > > On Wed, Mar 18, 2015 at 11:06:00AM -0700, Andy Lutomirski wrote: > > > > --- a/arch/x86/crtools.c > > > > +++ b/arch/x86/crtools.c > > > > @@ -475,6 +475,7 @@ int restore_gpregs(struct rt_sigframe *f, > > > > UserX86RegsEntry *r) > > > > CPREG2(rip, ip); > > > > CPREG2(eflags, flags); > > > > CPREG1(cs); > > > > + CPREG1(ss); > > > > CPREG1(gs); > > > > CPREG1(fs); > > > > > > Huh? Is CRIU actually trying to build an entire sigcontext from > > > scratch here? I don't see how this can reliably work across kernel > > > versions or CPU versions. > > > > Yes we are. And why it can't work reliably? As to CPU -- we're > > testing that cpu features saved in image should match ones > > provided by the kernel runtime, ie on the machine where we're > > restoring. > > But, say, __USER_CS can be changed in kernel, and nobody should notice this.
True (and this applies to quotes below). Hopefully it won't be changed frequently though ;) As to seg registers sure the safe way as Andy pointed is to fetch them runtime on the machine we're restoring. Thanks, I will update our code! > > But in this case "restore on another machine" or "restore after kernel > upgrade" can fail. > > So probably restore_gpregs() should only change the general-purpose regs, > as its name suggests. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
