linux-kernel - [PATCH 03/11] perf probe: Adjust map->reloc offset when finding kernel symbol from map

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Date:	Tue,  9 Aug 2016 13:01:26 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel@...r.kernel.org,
	Masami Hiramatsu <masami.hiramatsu@...aro.org>,
	Alexei Starovoitov <alexei.starovoitov@...il.com>,
	Wang Nan <wangnan0@...wei.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 03/11] perf probe: Adjust map->reloc offset when finding kernel symbol from map

From: Masami Hiramatsu <masami.hiramatsu@...aro.org>

Adjust map->reloc offset for the unmapped address when finding
alternative symbol address from map, because KASLR can relocate the
kernel symbol address.

The same adjustment has been done when finding appropriate kernel symbol
address from map which was introduced by commit f90acac75713 ("perf
probe: Find given address from offline dwarf")

Reported-by: Arnaldo Carvalho de Melo <acme@...nel.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu@...aro.org>
Cc: Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc: Wang Nan <wangnan0@...wei.com>
Link: http://lkml.kernel.org/r/20160806192948.e366f3fbc4b194de600f8326@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/util/probe-event.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 953dc1ab2ed7..d5ccb656fd81 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -385,7 +385,7 @@ static int find_alternative_probe_point(struct debuginfo *dinfo,
 		if (uprobes)
 			address = sym->start;
 		else
-			address = map->unmap_ip(map, sym->start);
+			address = map->unmap_ip(map, sym->start) - map->reloc;
 		break;
 	}
 	if (!address) {
-- 
2.7.4