On Fri, Mar 16, 2018 at 06:45:29PM +0100, Borislav Petkov wrote: > > You're better off getting rid of the CR2 line from __show_regs(), > > because it can be dangerously confusing. It's not actually part of the > > saved register state at all, it's something entirely different. It's > > like showing the current eflags rather than the eflags saved on the > > faulting stack. > > Yeah, __show_regs() goes and gets a bunch of registers at the time > __show_regs() runs. Which is ok for those which don't change in between > but CR2 is special. > > We probably could improve that situation by having a struct fault_regs > or so wrapping pt_regs and adding a bunch of fields like CR2 etc. Fault > handlers would then populate fault_regs at fault time while we're atomic > and then hand this struct down to the printing path. > > The printing path would fill out the rest and this way we won't have any > of that monkey business anymore. > > Thoughts?
It would be nice if we could save *all* the printed registers before they get a chance to change, but I don't know how feasible that is. Some of the registers change in entry code, like CR3 and GS. -- Josh
