On Wed, Aug 02, 2023 at 12:21:59PM +0100, Alan Maguire wrote:
SNIP
> > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> > index c92eb8c6ff08..7930a91ca7f3 100644
> > --- a/kernel/trace/bpf_trace.c
> > +++ b/kernel/trace/bpf_trace.c
> > @@ -1057,9 +1057,28 @@ static unsigned long get_entry_ip(unsigned long fentry_ip)
> > #define get_entry_ip(fentry_ip) fentry_ip
> > #endif
> >
> > +#ifdef CONFIG_UPROBES
> > +static unsigned long bpf_get_func_ip_uprobe(struct pt_regs *regs)
> > +{
> > + struct uprobe_dispatch_data *udd;
> > +
> > + udd = (struct uprobe_dispatch_data *) current->utask->vaddr;
> > + return udd->bp_addr;
> > +}
> > +#else
> > +#define bpf_get_func_ip_uprobe(regs) (u64) -1
>
> Small thing - I don't think this value is exposed to users due to the
> run_ctx->is_uprobe predicate, but would it be worth using -EOPNOTSUPP
> here maybe?
I initially thought of putting WARN_ON_ONCE in here, but as you said it
won't trigger so ended up with -1 .. but I don't mind using -EOPNOTSUPP
jirka
>
> > +#endif
> > +
> > BPF_CALL_1(bpf_get_func_ip_kprobe, struct pt_regs *, regs)
> > {
> > - struct kprobe *kp = kprobe_running();
> > + struct bpf_trace_run_ctx *run_ctx;
> > + struct kprobe *kp;
> > +
> > + run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx);
> > + if (run_ctx->is_uprobe)
> > + return bpf_get_func_ip_uprobe(regs);
> > +
> > + kp = kprobe_running();
> >
> > if (!kp || !(kp->flags & KPROBE_FLAG_ON_FUNC_ENTRY))
> > return 0;
> > diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
> > index 01ea148723de..7dde806be91e 100644
> > --- a/kernel/trace/trace_probe.h
> > +++ b/kernel/trace/trace_probe.h
> > @@ -519,3 +519,8 @@ void __trace_probe_log_err(int offset, int err);
> >
> > #define trace_probe_log_err(offs, err) \
> > __trace_probe_log_err(offs, TP_ERR_##err)
> > +
> > +struct uprobe_dispatch_data {
> > + struct trace_uprobe *tu;
> > + unsigned long bp_addr;
> > +};
> > diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> > index 555c223c3232..fc76c3985672 100644
> > --- a/kernel/trace/trace_uprobe.c
> > +++ b/kernel/trace/trace_uprobe.c
> > @@ -88,11 +88,6 @@ static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev)
> > static int register_uprobe_event(struct trace_uprobe *tu);
> > static int unregister_uprobe_event(struct trace_uprobe *tu);
> >
> > -struct uprobe_dispatch_data {
> > - struct trace_uprobe *tu;
> > - unsigned long bp_addr;
> > -};
> > -
> > static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
> > static int uretprobe_dispatcher(struct uprobe_consumer *con,
> > unsigned long func, struct pt_regs *regs);
> > diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> > index 70da85200695..d21deb46f49f 100644
> > --- a/tools/include/uapi/linux/bpf.h
> > +++ b/tools/include/uapi/linux/bpf.h
> > @@ -5086,9 +5086,14 @@ union bpf_attr {
> > * u64 bpf_get_func_ip(void *ctx)
> > * Description
> > * Get address of the traced function (for tracing and kprobe programs).
> > + *
> > + * When called for kprobe program attached as uprobe it returns
> > + * probe address for both entry and return uprobe.
> > + *
> > * Return
> > - * Address of the traced function.
> > + * Address of the traced function for kprobe.
> > * 0 for kprobes placed within the function (not at the entry).
> > + * Address of the probe for uprobe and return uprobe.
> > *
> > * u64 bpf_get_attach_cookie(void *ctx)
> > * Description
