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Subject[tip:perf/urgent] perf probe: Add error checks to offline probe post-processing
Commit-ID:  3e96dac7c956089d3f23aca98c4dfca57b6aaf8a
Gitweb: http://git.kernel.org/tip/3e96dac7c956089d3f23aca98c4dfca57b6aaf8a
Author: Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Wed, 11 Jan 2017 15:00:47 +0900
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 16 Jan 2017 15:35:25 -0300

perf probe: Add error checks to offline probe post-processing

Add error check codes on post processing and improve it for offline
probe events as:

- post processing fails if no matched symbol found in map(-ENOENT)
or strdup() failed(-ENOMEM).

- Even if the symbol name is the same, it updates symbol address
and offset.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/148411443738.9978.4617979132625405545.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/probe-event.c | 50 ++++++++++++++++++++++++++++---------------
1 file changed, 33 insertions(+), 17 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 4a57c8a..aa8a922 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -610,6 +610,33 @@ error:
return ret ? : -ENOENT;
}

+/* Adjust symbol name and address */
+static int post_process_probe_trace_point(struct probe_trace_point *tp,
+ struct map *map, unsigned long offs)
+{
+ struct symbol *sym;
+ u64 addr = tp->address + tp->offset - offs;
+
+ sym = map__find_symbol(map, addr);
+ if (!sym)
+ return -ENOENT;
+
+ if (strcmp(sym->name, tp->symbol)) {
+ /* If we have no realname, use symbol for it */
+ if (!tp->realname)
+ tp->realname = tp->symbol;
+ else
+ free(tp->symbol);
+ tp->symbol = strdup(sym->name);
+ if (!tp->symbol)
+ return -ENOMEM;
+ }
+ tp->offset = addr - sym->start;
+ tp->address -= offs;
+
+ return 0;
+}
+
/*
* Rename DWARF symbols to ELF symbols -- gcc sometimes optimizes functions
* and generate new symbols with suffixes such as .constprop.N or .isra.N
@@ -622,11 +649,9 @@ static int
post_process_offline_probe_trace_events(struct probe_trace_event *tevs,
int ntevs, const char *pathname)
{
- struct symbol *sym;
struct map *map;
unsigned long stext = 0;
- u64 addr;
- int i;
+ int i, ret = 0;

/* Prepare a map for offline binary */
map = dso__new_map(pathname);
@@ -636,23 +661,14 @@ post_process_offline_probe_trace_events(struct probe_trace_event *tevs,
}

for (i = 0; i < ntevs; i++) {
- addr = tevs[i].point.address + tevs[i].point.offset - stext;
- sym = map__find_symbol(map, addr);
- if (!sym)
- continue;
- if (!strcmp(sym->name, tevs[i].point.symbol))
- continue;
- /* If we have no realname, use symbol for it */
- if (!tevs[i].point.realname)
- tevs[i].point.realname = tevs[i].point.symbol;
- else
- free(tevs[i].point.symbol);
- tevs[i].point.symbol = strdup(sym->name);
- tevs[i].point.offset = addr - sym->start;
+ ret = post_process_probe_trace_point(&tevs[i].point,
+ map, stext);
+ if (ret < 0)
+ break;
}
map__put(map);

- return 0;
+ return ret;
}

static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs,
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