perf probe: Fix to adjust symbol address with correct reloc_sym address

'perf probe' uses ref_reloc_sym to adjust symbol offset address from
debuginfo address or ref_reloc_sym based address, but that is misusing
reloc_sym->addr and reloc_sym->unrelocated_addr.  If map is not
relocated (map->reloc == 0), we can use reloc_sym->addr as unrelocated
address instead of reloc_sym->unrelocated_addr.

This usually does not happen. If we have a non-stripped ELF binary, we
will use it for map and debuginfo, if not, we use only kallsyms without
debuginfo. Thus, the map is always relocated (ELF and DWARF binary) or
not relocated (kallsyms).

However, if we allow the combination of debuginfo and kallsyms based map
(like using debuginfod), we have to check the map->reloc and choose the
collect address of reloc_sym.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Frank Ch. Eigler <fche@redhat.com>
Cc: Aaron Merey <amerey@redhat.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Link: http://lore.kernel.org/lkml/160041609047.912668.14314639291419159274.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 99d36ac..17831f1 100644 (file)
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -129,9 +129,10 @@ static int kernel_get_symbol_address_by_name(const char *name, u64 *addr,
        struct map *map;
 
        /* ref_reloc_sym is just a label. Need a special fix*/
-       reloc_sym = kernel_get_ref_reloc_sym(NULL);
+       reloc_sym = kernel_get_ref_reloc_sym(&map);
        if (reloc_sym && strcmp(name, reloc_sym->name) == 0)
-               *addr = (reloc) ? reloc_sym->addr : reloc_sym->unrelocated_addr;
+               *addr = (!map->reloc || reloc) ? reloc_sym->addr :
+                       reloc_sym->unrelocated_addr;
        else {
                sym = machine__find_kernel_symbol_by_name(host_machine, name, &map);
                if (!sym)
@@ -795,7 +796,8 @@ post_process_kernel_probe_trace_events(struct probe_trace_event *tevs,
                        free(tevs[i].point.symbol);
                tevs[i].point.symbol = tmp;
                tevs[i].point.offset = tevs[i].point.address -
-                                      reloc_sym->unrelocated_addr;
+                       (map->reloc ? reloc_sym->unrelocated_addr :
+                                     reloc_sym->addr);
        }
        return skipped;
 }