[PATCH 5.4 245/434] perf probe: Fix to list probe event with correct line number

Greg Kroah-Hartman
2019-12-29T18:05:37Z

From: Masami Hiramatsu <mhiramat@kernel.org>

[ Upstream commit 3895534dd78f0fd4d3f9e05ee52b9cdd444a743e ]

Since debuginfo__find_probe_point() uses dwarf_entrypc() for finding the
entry address of the function on which a probe is, it will fail when the
function DIE has only ranges attribute.

To fix this issue, use die_entrypc() instead of dwarf_entrypc().

Without this fix, perf probe -l shows incorrect offset:

# perf probe -l
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask+18446744071579263632@work/linux/linux/kernel/cpu.c)
probe:clear_tasks_mm_cpumask_1 (on clear_tasks_mm_cpumask+18446744071579263752@work/linux/linux/kernel/cpu.c)

With this:

# perf probe -l
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask@work/linux/linux/kernel/cpu.c)
probe:clear_tasks_mm_cpumask_1 (on clear_tasks_mm_cpumask:21@work/linux/linux/kernel/cpu.c)

Committer testing:

Before:

[root@quaco ~]# perf probe -l
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask+18446744071579765152@kernel/cpu.c)
[root@quaco ~]#

After:

[root@quaco ~]# perf probe -l
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask@kernel/cpu.c)
[root@quaco ~]#

Fixes: 1d46ea2a6a40 ("perf probe: Fix listing incorrect line number with inline function")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157199321227.8075.14655572419136993015.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/util/probe-finder.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index cd9f95e5044e..7c8d30fb2b99 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1578,7 +1578,7 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
/* Get function entry information */
func = basefunc = dwarf_diename(&spdie);
if (!func ||
- dwarf_entrypc(&spdie, &baseaddr) != 0 ||
+ die_entrypc(&spdie, &baseaddr) != 0 ||
dwarf_decl_line(&spdie, &baseline) != 0) {
lineno = 0;
goto post;
@@ -1595,7 +1595,7 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
&indie)) {
/* There is an inline function */
- if (dwarf_entrypc(&indie, &_addr) == 0 &&
+ if (die_entrypc(&indie, &_addr) == 0 &&
_addr == addr) {
/*
* addr is at an inline function entry.
--
2.20.1