This is a note to let you know that I've just added the patch titled perf inject: Use perf_data__read() for auxtrace to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: perf-inject-use-perf_data__read-for-auxtrace.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 21a44645b607233897c5b4922884439558510390 Author: Namhyung Kim <namhyung@xxxxxxxxxx> Date: Mon Jan 30 18:33:47 2023 -0800 perf inject: Use perf_data__read() for auxtrace [ Upstream commit 1746212daeba95e9ae1639227dc0c3591d41deeb ] In copy_bytes(), it reads the data from the (input) fd and writes it to the output file. But it does with the read(2) unconditionally which caused a problem of mixing buffered vs unbuffered I/O together. You can see the problem when using pipes. $ perf record -e intel_pt// -o- true | perf inject -b > /dev/null [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.000 MB - ] 0x45c0 [0x30]: failed to process type: 71 It should use perf_data__read() to honor the 'use_stdio' setting. Fixes: 601366678c93618f ("perf data: Allow to use stdio functions for pipe mode") Reviewed-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> Reviewed-by: James Clark <james.clark@xxxxxxx> Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx> Cc: Ian Rogers <irogers@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: Leo Yan <leo.yan@xxxxxxxxxx> Cc: Namhyung Kim <namhyung@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Stephane Eranian <eranian@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230131023350.1903992-2-namhyung@xxxxxxxxxx Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c index 50c2e6892b3e9..f15c146e00548 100644 --- a/tools/perf/builtin-inject.c +++ b/tools/perf/builtin-inject.c @@ -142,14 +142,14 @@ static int perf_event__repipe_event_update(struct perf_tool *tool, #ifdef HAVE_AUXTRACE_SUPPORT -static int copy_bytes(struct perf_inject *inject, int fd, off_t size) +static int copy_bytes(struct perf_inject *inject, struct perf_data *data, off_t size) { char buf[4096]; ssize_t ssz; int ret; while (size > 0) { - ssz = read(fd, buf, min(size, (off_t)sizeof(buf))); + ssz = perf_data__read(data, buf, min(size, (off_t)sizeof(buf))); if (ssz < 0) return -errno; ret = output_bytes(inject, buf, ssz); @@ -187,7 +187,7 @@ static s64 perf_event__repipe_auxtrace(struct perf_session *session, ret = output_bytes(inject, event, event->header.size); if (ret < 0) return ret; - ret = copy_bytes(inject, perf_data__fd(session->data), + ret = copy_bytes(inject, session->data, event->auxtrace.size); } else { ret = output_bytes(inject, event,