perf tools: Fixup end address of modules

In machine__create_module(), it reads /proc/modules to get a list of
modules in the system.  The file shows the start address (of text) and
the size of the module so it uses the info to reconstruct system memory
maps for symbol resolution.

But module memory consists of multiple segments and they can be
scaterred.  Currently perf tools assume they are contiguous and see some
overlaps.  This can confuse the tool when it finds a map containing a
given address.

As we mostly care about the function symbols in the text segment, it can
fixup the size or end address of modules when there's an overlap.  We
can use maps__fixup_end() which updates the end address using the start
address of the next map.

Ideally it should be able to track other segments (like data/rodata),
but that would require some changes in /proc/modules IMHO.

Reported-by: Blake Jones <blakejones@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20241218220453.203069-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 9be2f4479f52572c3687411d27b95d79d6139b5f..2d51badfbf2e2d1588fa4fdd42ef6c8fea35bf0e 100644 (file)
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1468,6 +1468,8 @@ static int machine__create_modules(struct machine *machine)
        if (modules__parse(modules, machine, machine__create_module))
                return -1;
 
+       maps__fixup_end(machine__kernel_maps(machine));
+
        if (!machine__set_modules_path(machine))
                return 0;