On 11/17, Jiri Olsa wrote: > > This patchset adds support to optimize uprobe on top of instruction > that could be emulated and also adds support to emulate particular > versions of mov and sub instructions to cover some of the user space > functions prologues, like: > > pushq %rbp > movq %rsp,%rbp > subq $0xb0,%rsp
... > There's an additional issue that single instruction replacement does > not have and it's the possibility of the user space code to jump in the > middle of those 5 bytes. I think it's unlikely to happen at the function > prologue, but uprobe could be placed anywhere. I'm not sure how to > mitigate this other than having some enable/disable switch or config > option, which is unfortunate. plus this breaks single-stepping... Although perhaps we don't really care. Oleg.
