perf symbols: Use only --vmlinux if specified

Found while analysing a perf.data file collected on an ARM
machine where an explicitely specified vmlinux was being
disregarded.

Reported-by: Jamie Iles <jamie.iles@picochip.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1263904574-30732-2-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index a4e7459..b6ab23d 100644 (file)
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1572,7 +1572,7 @@ static int dso__load_vmlinux(struct dso *self, struct map *map,
                return -1;
 
        dso__set_loaded(self, map->type);
-       err = dso__load_sym(self, map, session, self->long_name, fd, filter, 1, 0);
+       err = dso__load_sym(self, map, session, vmlinux, fd, filter, 1, 0);
        close(fd);
 
        return err;
@@ -1584,6 +1584,26 @@ static int dso__load_kernel_sym(struct dso *self, struct map *map,
        int err;
        const char *kallsyms_filename = NULL;
        char *kallsyms_allocated_filename = NULL;
+       /*
+        * Step 1: if the user specified a vmlinux filename, use it and only
+        * it, reporting errors to the user if it cannot be used.
+        *
+        * For instance, try to analyse an ARM perf.data file _without_ a
+        * build-id, or if the user specifies the wrong path to the right
+        * vmlinux file, obviously we can't fallback to another vmlinux (a
+        * x86_86 one, on the machine where analysis is being performed, say),
+        * or worse, /proc/kallsyms.
+        *
+        * If the specified file _has_ a build-id and there is a build-id
+        * section in the perf.data file, we will still do the expected
+        * validation in dso__load_vmlinux and will bail out if they don't
+        * match.
+        */
+       if (symbol_conf.vmlinux_name != NULL) {
+               err = dso__load_vmlinux(self, map, session,
+                                       symbol_conf.vmlinux_name, filter);
+               goto out_try_fixup;
+       }
 
        if (vmlinux_path != NULL) {
                int i;
@@ -1618,46 +1638,41 @@ static int dso__load_kernel_sym(struct dso *self, struct map *map,
                                goto do_kallsyms;
                        }
                }
-
+               /*
+                * Now look if we have it on the build-id cache in
+                * $HOME/.debug/[kernel.kallsyms].
+                */
                build_id__sprintf(self->build_id, sizeof(self->build_id),
                                  sbuild_id);
 
                if (asprintf(&kallsyms_allocated_filename,
                             "%s/.debug/[kernel.kallsyms]/%s",
-                            getenv("HOME"), sbuild_id) != -1) {
-                       if (access(kallsyms_filename, F_OK)) {
-                               kallsyms_filename = kallsyms_allocated_filename;
-                               goto do_kallsyms;
-                       }
+                            getenv("HOME"), sbuild_id) == -1)
+                       return -1;
+
+               if (access(kallsyms_filename, F_OK)) {
                        free(kallsyms_allocated_filename);
-                       kallsyms_allocated_filename = NULL;
+                       return -1;
                }
 
-               goto do_vmlinux;
-       }
-
-       if (self->long_name[0] == '[') {
+               kallsyms_filename = kallsyms_allocated_filename;
+       } else {
+               /*
+                * Last resort, if we don't have a build-id and couldn't find
+                * any vmlinux file, try the running kernel kallsyms table.
+                */
                kallsyms_filename = "/proc/kallsyms";
-               goto do_kallsyms;
        }
 
-do_vmlinux:
-       err = dso__load_vmlinux(self, map, session, self->long_name, filter);
-       if (err <= 0) {
-               if (self->has_build_id)
-                       return -1;
-
-               pr_info("The file %s cannot be used, "
-                       "trying to use /proc/kallsyms...", self->long_name);
 do_kallsyms:
-               err = dso__load_kallsyms(self, kallsyms_filename, map, session, filter);
-               if (err > 0 && kallsyms_filename == NULL)
-                        dso__set_long_name(self, strdup("[kernel.kallsyms]"));
-               free(kallsyms_allocated_filename);
-       }
+       err = dso__load_kallsyms(self, kallsyms_filename, map, session, filter);
+       free(kallsyms_allocated_filename);
 
+out_try_fixup:
        if (err > 0) {
 out_fixup:
+               if (kallsyms_filename == NULL)
+                       dso__set_long_name(self, strdup("[kernel.kallsyms]"));
                map__fixup_start(map);
                map__fixup_end(map);
        }