perf symbols: Ignore ABS symbols when loading data maps

When loading symbols in a data mapping, ABS symbols (which has a value
of SHN_ABS in its st_shndx) failed at elf_getscn().  And it marks the
loading as a failure so already loaded symbols cannot be fixed up.

I'm not sure what should be done. Just ignore them for now. :)

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1353502185-26521-19-git-send-email-eranian@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/symbol-elf.c

@@ -718,6 +718,17 @@ int dso__load_sym(struct dso *dso, struct map *map,
 					sym.st_value);
 			used_opd = true;
 		}
+		/*
+		 * When loading symbols in a data mapping, ABS symbols (which
+		 * has a value of SHN_ABS in its st_shndx) failed at
+		 * elf_getscn().  And it marks the loading as a failure so
+		 * already loaded symbols cannot be fixed up.
+		 *
+		 * I'm not sure what should be done. Just ignore them for now.
+		 * - Namhyung Kim
+		 */
+		if (sym.st_shndx == SHN_ABS)
+			continue;
 
 		sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 		if (!sec)