Prev: Information about your X6 Concept Car.
Next: [GIT PULL] perf updates
From: Frederic Weisbecker on 9 May 2010 16:50
From: Tom Zanussi <tzanussi(a)gmail.com>

Some events, such as the PERF_RECORD_FINISHED_ROUND event consist of
only an event header and no data. In this case, a 0-length payload
will be read, and the 0 return value will be wrongly interpreted as an
'unexpected end of event stream'.

This patch allows for proper handling of data-less events by skipping
0-length reads.

Signed-off-by: Tom Zanussi <tzanussi(a)gmail.com>
Cc: Arnaldo Carvalho de Melo <acme(a)redhat.com>
Cc: Ingo Molnar <mingo(a)elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra(a)chello.nl>
Cc: Paul Mackerras <paulus(a)samba.org>
Cc: Masami Hiramatsu <mhiramat(a)redhat.com>
LKML-Reference: <1273038527.6383.51.camel(a)tropicana>
Signed-off-by: Frederic Weisbecker <fweisbec(a)gmail.com>
---
tools/perf/util/session.c | 19 +++++++++++--------
1 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 9401909..00ab298 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -696,15 +696,18 @@ more:
p = &event;
p += sizeof(struct perf_event_header);

- err = do_read(self->fd, p, size - sizeof(struct perf_event_header));
- if (err <= 0) {
- if (err == 0) {
- pr_err("unexpected end of event stream\n");
- goto done;
- }
+ if (size - sizeof(struct perf_event_header)) {
+ err = do_read(self->fd, p,
+ size - sizeof(struct perf_event_header));
+ if (err <= 0) {
+ if (err == 0) {
+ pr_err("unexpected end of event stream\n");
+ goto done;
+ }

- pr_err("failed to read event data\n");
- goto out_err;
+ pr_err("failed to read event data\n");
+ goto out_err;
+ }
}

if (size == 0 ||
--
1.6.2.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo(a)vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
 | 
Pages: 1
Prev: Information about your X6 Concept Car.
Next: [GIT PULL] perf updates