[tip:perf/core] perf probe: Fix line walker to check CU correctly

tip-bot for Masami Hiramatsu
2011-08-14T15:41:09Z

Commit-ID: a128405c6b40371c59c34b00cc66ed06285b9551
Gitweb: http://git.kernel.org/tip/a128405c6b40371c59c34b00cc66ed06285b9551
Author: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 11 Aug 2011 20:02:35 +0900
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 12 Aug 2011 09:22:46 -0300

perf probe: Fix line walker to check CU correctly

Fix line walker to check whether a given DIE is CU or not.

Actually this function accepts CU, subprogram and inlined_subroutine
DIEs.

Without this fix, perf probe always fails to analyze lines on inlined
functions;

$ perf probe -L pre_schedule
Debuginfo analysis failed. (-2)
Error: Failed to show lines. (-2)

This fixes that bug, as below.

$ perf probe -L pre_schedule
<pre_schedule@/home/mhiramat/ksrc/linux-2.6/kernel/sched.c:0>
0 static inline void pre_schedule(struct rq *rq, struct task_struct *prev
{
2 if (prev->sched_class->pre_schedule)
3 prev->sched_class->pre_schedule(rq, prev);
}

/* rq->lock is NOT held, but preemption is disabled */

Changes from v1:
- Update against current tip tree.(Fix dwarf-aux.c)

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <masami.hiramatsu@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/20110811110235.19900.20614.stgit@fedora15
Signed-off-by: Masami Hiramatsu <masami.hiramatsu@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/dwarf-aux.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index fddf40f..d35b454 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -439,7 +439,7 @@ static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)

/**
* die_walk_lines - Walk on lines inside given DIE
- * @rt_die: a root DIE (CU or subprogram)
+ * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
* @callback: callback routine
* @data: user data
*
@@ -460,12 +460,12 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
size_t nlines, i;

/* Get the CU die */
- if (dwarf_tag(rt_die) == DW_TAG_subprogram)
+ if (dwarf_tag(rt_die) != DW_TAG_compile_unit)
cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
else
cu_die = rt_die;
if (!cu_die) {
- pr_debug2("Failed to get CU from subprogram\n");
+ pr_debug2("Failed to get CU from given DIE.\n");
return -EINVAL;
}