4.9-stable review patch. If anyone has any objections, please let me know.
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From: David Carrillo-Cisneros davidcc@google.com
[ Upstream commit 1e0d4f0200e4dbdfc38d818f329d8a0955f7c6f5 ]
__perf_session__process_pipe_events reuses the same memory buffer to process all events in the pipe.
When reordering is needed (e.g. -b option), events are not immediately flushed, but kept around until reordering is possible, causing memory corruption.
The problem is usually observed by a "Unknown sample error" output. It can easily be reproduced by:
perf record -o - noploop | perf inject -b > output
Committer testing:
Before:
$ perf record -o - stress -t 2 -c 2 | perf inject -b > /dev/null stress: info: [8297] dispatching hogs: 2 cpu, 0 io, 0 vm, 0 hdd stress: info: [8297] successful run completed in 2s [ perf record: Woken up 3 times to write data ] [ perf record: Captured and wrote 0.000 MB - ] Warning: Found 1 unknown events!
Is this an older tool processing a perf.data file generated by a more recent tool?
If that is not the case, consider reporting to linux-kernel@vger.kernel.org.
$
After:
$ perf record -o - stress -t 2 -c 2 | perf inject -b > /dev/null stress: info: [9027] dispatching hogs: 2 cpu, 0 io, 0 vm, 0 hdd stress: info: [9027] successful run completed in 2s [ perf record: Woken up 3 times to write data ] [ perf record: Captured and wrote 0.000 MB - ] no symbols found in /usr/bin/stress, maybe install a debug package? no symbols found in /usr/bin/stress, maybe install a debug package? $
Signed-off-by: David Carrillo-Cisneros davidcc@google.com Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Acked-by: Jiri Olsa jolsa@kernel.org Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Andi Kleen ak@linux.intel.com Cc: He Kuang hekuang@huawei.com Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Paul Turner pjt@google.com Cc: Peter Zijlstra peterz@infradead.org Cc: Simon Que sque@chromium.org Cc: Stephane Eranian eranian@google.com Cc: Wang Nan wangnan0@huawei.com Link: http://lkml.kernel.org/r/20170410201432.24807-3-davidcc@google.com Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/perf/util/ordered-events.c | 3 ++- tools/perf/util/session.c | 1 + 2 files changed, 3 insertions(+), 1 deletion(-)
--- a/tools/perf/util/ordered-events.c +++ b/tools/perf/util/ordered-events.c @@ -79,7 +79,7 @@ static union perf_event *dup_event(struc
static void free_dup_event(struct ordered_events *oe, union perf_event *event) { - if (oe->copy_on_queue) { + if (event && oe->copy_on_queue) { oe->cur_alloc_size -= event->header.size; free(event); } @@ -150,6 +150,7 @@ void ordered_events__delete(struct order list_move(&event->list, &oe->cache); oe->nr_events--; free_dup_event(oe, event->event); + event->event = NULL; }
int ordered_events__queue(struct ordered_events *oe, union perf_event *event, --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -1628,6 +1628,7 @@ static int __perf_session__process_pipe_ buf = malloc(cur_size); if (!buf) return -errno; + ordered_events__set_copy_on_queue(oe, true); more: event = buf; err = readn(fd, event, sizeof(struct perf_event_header));