On Tue, Apr 02, 2019 at 10:51:49AM -0500, Josh Poimboeuf wrote: > On Tue, Apr 02, 2019 at 05:48:56PM +0200, Thomas Gleixner wrote: > > > With the above "(stk <= begin || stk >= end)" check, removing the loop > > > becomes not all that important since exception stack dumps are quite > > > rare and not performance sensitive. With all the macros this code > > > becomes a little more obtuse, so I'm not sure whether removal of the > > > loop is a net positive. > > > > What about perf? It's NMI context and probably starts from there. Peter? > > I believe perf unwinds starting from the regs from the context which was > interrupted by the NMI.
Aah, indeed. So then we only see exception stacks when the NMI lands in an exception, which is, as you say, quite rare.
