linux-kernel - [PATCH 1/1] perf symbols: Fix up map end too on modular kernels with no modules installed

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Date:	Sat, 20 Feb 2010 19:53:13 -0200
From:	Arnaldo Carvalho de Melo <acme@...radead.org>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	linux-kernel@...r.kernel.org,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Frédéric Weisbecker <fweisbec@...il.com>,
	Mike Galbraith <efault@....de>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>
Subject: [PATCH 1/1] perf symbols: Fix up map end too on modular kernels with no modules installed

From: Arnaldo Carvalho de Melo <acme@...hat.com>

In 2161db9 we stopped failing when not finding modules when asked too,
but then the kernel maps (just one, for vmlinux) wasn't having its ->end
field correctly set up, so symbols were not being found for the vmlinux
map because its range was 0-0.

Reported-by: Ingo Molnar <mingo@...e.hu>
Cc: Frédéric Weisbecker <fweisbec@...il.com>
Cc: Mike Galbraith <efault@....de>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Paul Mackerras <paulus@...ba.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/util/event.c  |    6 ++++++
 tools/perf/util/symbol.c |    2 +-
 2 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 5a99e61..705ec63 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -379,6 +379,12 @@ int event__process_mmap(event_t *self, struct perf_session *session)
 
 			session->vmlinux_maps[MAP__FUNCTION]->start = self->mmap.start;
 			session->vmlinux_maps[MAP__FUNCTION]->end   = self->mmap.start + self->mmap.len;
+			/*
+			 * Be a bit paranoid here, some perf.data file came with
+			 * a zero sized synthesized MMAP event for the kernel.
+			 */
+			if (session->vmlinux_maps[MAP__FUNCTION]->end == 0)
+				session->vmlinux_maps[MAP__FUNCTION]->end = ~0UL;
 
 			perf_session__set_kallsyms_ref_reloc_sym(session, symbol_name,
 								 self->mmap.pgoff);
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 6882e9f..ee9c37e 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1937,7 +1937,7 @@ int map_groups__create_kernel_maps(struct map_groups *self,
 		return -1;
 
 	if (symbol_conf.use_modules && map_groups__create_modules(self) < 0)
-		return 0;
+		pr_debug("Problems creating module maps, continuing anyway...\n");
 	/*
 	 * Now that we have all the maps created, just set the ->end of them:
 	 */
-- 
1.6.2.5

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