15:31 <ggherdov> Hello. If, given a probepoint, I know the position on the stack of some data I care about (eg. some offset from the base pointer $rbp etc) when that probepoint is hit, can I read such data w/ systemtap?

15:32 <fche> usually you don't have to do such machinations, because parameters are available symbolically via $foo etc.

15:32 <fche> but if you do have to, you could use register("rbp") or something to fetch the current register value, then do some of your own arithmetic, and dereference the resulting address with (say) kernel_long(addr)

15:34 <ggherdov> fche: right, but using `stap -L probepoint` the variable isn't visible (maybe optimized away). Readying the disassembled code, I think I know where the data is.

15:34 <ggherdov> Thanks for the suggestion of register("rbp"), I didn't know about it