On Mon, 24 Nov 2025 19:12:42 +0100 Oleg Nesterov <[email protected]> wrote:
> 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. Yeah, and I think we can stop optimization if post_handler is set. Thanks, -- Masami Hiramatsu (Google) <[email protected]>
