[tip:perf/core] perf probe: Fix list result when symbol can' t be found

From: tip-bot for Wang Nan
Date: Fri Aug 28 2015 - 02:42:27 EST

Commit-ID: 614e2fdbd79b47ddf63a1ccd3f2343e98c3077fb
Gitweb: http://git.kernel.org/tip/614e2fdbd79b47ddf63a1ccd3f2343e98c3077fb
Author: Wang Nan <wangnan0@xxxxxxxxxx>
AuthorDate: Wed, 26 Aug 2015 10:57:42 +0000
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 26 Aug 2015 10:36:04 -0300

perf probe: Fix list result when symbol can't be found

'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>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
Link: http://lkml.kernel.org/r/1440586666-235233-4-git-send-email-wangnan0@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
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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