On Sun, Dec 17, 2023 at 1:55 PM Jiri Olsa <jolsa@xxxxxxxxxx> wrote: > > Currently the __uprobe_register will return 0 (success) when called with > negative offset. The reason is that the call to register_for_each_vma and > then build_map_info won't return error for negative offset. They just won't > do anything - no matching vma is found so there's no registered breakpoint > for the uprobe. > > I don't think we can change the behaviour of __uprobe_register and fail > for negative uprobe offset, because apps might depend on that already. > > But I think we can still make the change and check for it on bpf multi > link syscall level. > > Also moving the __get_user call and check for the offsets to the top of > loop, to fail early without extra __get_user calls for ref_ctr_offset > and cookie arrays. > > Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx> Acked-by: Song Liu <song@xxxxxxxxxx>
