linux-kernel - [PATCH 1/1 perf-tools-next] perf top: Don't complain about lack of vmlinux when not resolving some kernel samples

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Message-ID: <Z3gUl1guIXi4bU0a@x1>
Date: Fri, 3 Jan 2025 13:47:19 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Ian Rogers <irogers@...gle.com>,
	James Clark <james.clark@...aro.org>, Jiri Olsa <jolsa@...nel.org>,
	Kan Liang <kan.liang@...ux.intel.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	linux-perf-users@...r.kernel.org
Subject: [PATCH 1/1 perf-tools-next] perf top: Don't complain about lack of
 vmlinux when not resolving some kernel samples

Recently we got a case where a kernel sample wasn't being resolved due
to a bug that was not setting the end address on kernel functions
implemented in assembly (see Link: tag), and then those were not being
found by machine__resolve() -> map__find_symbol().

So we ended up with:

  # perf top --stdio
  PerfTop: 0 irqs/s  kernel: 0%  exact: 0% lost: 0/0 drop: 0/0 [cycles/P]
  -----------------------------------------------------------------------

  Warning:
  A vmlinux file was not found.
  Kernel samples will not be resolved.
  ^Z
  [1]+  Stopped                 perf top --stdio
  #

But then resolving all other kernel symbols.

So just fixup the logic to only print that warning when there are no
symbols in the kernel map.

Cc: Adrian Hunter <adrian.hunter@...el.com>
Cc: Ian Rogers <irogers@...gle.com>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>
Cc: James Clark <james.clark@...aro.org>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Kan Liang <kan.liang@...ux.intel.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Link: https://lore.kernel.org/lkml/Z3buKhcCsZi3_aGb@x1
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/builtin-top.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 724a7938632126bf..ca3e8eca6610e851 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -809,7 +809,7 @@ static void perf_event__process_sample(const struct perf_tool *tool,
 		 * invalid --vmlinux ;-)
 		 */
 		if (!machine->kptr_restrict_warned && !top->vmlinux_warned &&
-		    __map__is_kernel(al.map) && map__has_symbols(al.map)) {
+		    __map__is_kernel(al.map) && !map__has_symbols(al.map)) {
 			if (symbol_conf.vmlinux_name) {
 				char serr[256];
 
-- 
2.47.0