On Wed, Jul 5, 2023 at 4:26 PM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote:
>
> On 6/28/23 1:53 PM, Yafang Shao wrote:
> > Since different symbols can share the same name, it is insufficient to only
> > expose the symbol name. It is essential to also expose the symbol address
> > so that users can accurately identify which one is being probed.
> >
> > Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> > ---
> > kernel/trace/trace_kprobe.c | 10 +++++-----
> > 1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> > index e4554dbfd113..17e17298e894 100644
> > --- a/kernel/trace/trace_kprobe.c
> > +++ b/kernel/trace/trace_kprobe.c
> > @@ -1547,15 +1547,15 @@ int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
> > if (tk->symbol) {
> > *symbol = tk->symbol;
> > *probe_offset = tk->rp.kp.offset;
> > - *probe_addr = 0;
> > } else {
> > *symbol = NULL;
> > *probe_offset = 0;
> > - if (kallsyms_show_value(current_cred()))
> > - *probe_addr = (unsigned long)tk->rp.kp.addr;
> > - else
> > - *probe_addr = 0;
> > }
> > +
> > + if (kallsyms_show_value(current_cred()))
> > + *probe_addr = (unsigned long)tk->rp.kp.addr;
> > + else
> > + *probe_addr = 0;
> > return 0;
>
> Can't this be simplified further? If tk->symbol is NULL we assign NULL anyway:
Agree. Thanks.
>
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 1b3fa7b854aa..bf2872ca5aaf 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -1544,15 +1544,10 @@ int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
>
> *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
> : BPF_FD_TYPE_KPROBE;
> - if (tk->symbol) {
> - *symbol = tk->symbol;
> - *probe_offset = tk->rp.kp.offset;
> - *probe_addr = 0;
> - } else {
> - *symbol = NULL;
> - *probe_offset = 0;
> - *probe_addr = (unsigned long)tk->rp.kp.addr;
> - }
> + *probe_offset = tk->rp.kp.offset;
> + *probe_addr = kallsyms_show_value(current_cred()) ?
> + (unsigned long)tk->rp.kp.addr : 0;
> + *symbol = tk->symbol;
> return 0;
> }
> #endif /* CONFIG_PERF_EVENTS */
>
--
Regards
Yafang
