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authorLeo Yan <leo.yan@linaro.org>2021-06-05 08:29:57 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2021-06-11 18:54:24 +0300
commit197eecb6ecae0b04bd694432f640ff75597fed9c (patch)
tree4bfc1b92225ba91c80725214098f380901d7921d
parent06af8679449d4ed282df13191fc52d5ba28ec536 (diff)
downloadlinux-197eecb6ecae0b04bd694432f640ff75597fed9c.tar.xz
perf session: Correct buffer copying when peeking events
When peeking an event, it has a short path and a long path. The short path uses the session pointer "one_mmap_addr" to directly fetch the event; and the long path needs to read out the event header and the following event data from file and fill into the buffer pointer passed through the argument "buf". The issue is in the long path that it copies the event header and event data into the same destination address which pointer "buf", this means the event header is overwritten. We are just lucky to run into the short path in most cases, so we don't hit the issue in the long path. This patch adds the offset "hdr_sz" to the pointer "buf" when copying the event data, so that it can reserve the event header which can be used properly by its caller. Fixes: 5a52f33adf02 ("perf session: Add perf_session__peek_event()") Signed-off-by: Leo Yan <leo.yan@linaro.org> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Acked-by: Jiri Olsa <jolsa@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lore.kernel.org/lkml/20210605052957.1070720-1-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-rw-r--r--tools/perf/util/session.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 106b3d60881a..e59242c361ce 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1723,6 +1723,7 @@ int perf_session__peek_event(struct perf_session *session, off_t file_offset,
if (event->header.size < hdr_sz || event->header.size > buf_sz)
return -1;
+ buf += hdr_sz;
rest = event->header.size - hdr_sz;
if (readn(fd, buf, rest) != (ssize_t)rest)