[PATCH v3 2/6] perf probe: Fix list result when neither dwarf nor map can't find symbol

From: Wang Nan
Date: Wed Aug 26 2015 - 06:59:59 EST

'perf probe -l' reports error if it is unable find symbol through
address. Here is an example.

# echo 'p:probe_libc/abs_5 /lib64/libc.so.6:0x5' >
# cat /sys/kernel/debug/tracing/uprobe_events
p:probe_libc/abs_5 /lib64/libc.so.6:0x0000000000000005
# perf probe -l
Error: Failed to show event list

Also, this situation triggers a logical inconsistency in
convert_to_perf_probe_point() that, it returns ENOMEM but actually
it never try strdup().

This patch removes !tp->module && !is_kprobe condition, so it
always uses address to build function name if symbol not found.

Test result:

# perf probe -l
probe_libc:abs_5 (on 0x5 in /lib64/libc.so.6)

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
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 6c7e538..f7bacbb 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1866,7 +1866,7 @@ static int convert_to_perf_probe_point(struct probe_trace_point *tp,
if (tp->symbol) {
pp->function = strdup(tp->symbol);
pp->offset = tp->offset;
- } else if (!tp->module && !is_kprobe) {
+ } else {
ret = e_snprintf(buf, 128, "0x%" PRIx64, (u64)tp->address);
if (ret < 0)
return ret;

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