From fea20d66f90cdbdc7dccf1fa001d40e084984e55 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Mon, 19 Jul 2021 15:31:51 -0700 Subject: [PATCH] perf inject: Fix output from a pipe to a file Sometimes it needs to save the perf inject data to a file for debugging. But normally it assumes the same format for input and output, so the end result cannot be used due to a broken format. # perf record -a -o - sleep 1 | perf inject -b -o my.data # perf report -i my.data --stdio 0x208 [0]: failed to process type: 0 [Invalid argument] Error: failed to process sample # To display the perf.data header info, please use --header/--header-only options. # In this case, it thought the data has a regular file header since the output is not a pipe. But actually it doesn't have one and has a pipe file header. At the end of the session, it tries to rewrite the regular file header with updated features and it overwrites the data just follows the pipe header. Fix it by checking either the input and the output is a pipe. Signed-off-by: Namhyung Kim Acked-by: Jiri Olsa Cc: Adrian Hunter Cc: Andi Kleen Cc: Ian Rogers Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/20210719223153.1618812-4-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-inject.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c index 01afa96..f9af243 100644 --- a/tools/perf/builtin-inject.c +++ b/tools/perf/builtin-inject.c @@ -46,6 +46,7 @@ struct perf_inject { bool jit_mode; bool in_place_update; bool in_place_update_dry_run; + bool is_pipe; const char *input_name; struct perf_data output; u64 bytes_written; @@ -126,7 +127,7 @@ static int perf_event__repipe_attr(struct perf_tool *tool, if (ret) return ret; - if (!inject->output.is_pipe) + if (!inject->is_pipe) return 0; return perf_event__repipe_synth(tool, event); @@ -826,14 +827,14 @@ static int __cmd_inject(struct perf_inject *inject) if (!inject->itrace_synth_opts.set) auxtrace_index__free(&session->auxtrace_index); - if (!data_out->is_pipe && !inject->in_place_update) + if (!inject->is_pipe && !inject->in_place_update) lseek(fd, output_data_offset, SEEK_SET); ret = perf_session__process_events(session); if (ret) return ret; - if (!data_out->is_pipe && !inject->in_place_update) { + if (!inject->is_pipe && !inject->in_place_update) { if (inject->build_ids) perf_header__set_feat(&session->header, HEADER_BUILD_ID); @@ -992,8 +993,12 @@ int cmd_inject(int argc, const char **argv) } data.path = inject.input_name; - inject.session = __perf_session__new(&data, inject.output.is_pipe, - perf_data__fd(&inject.output), &inject.tool); + if (!strcmp(inject.input_name, "-") || inject.output.is_pipe) + inject.is_pipe = true; + + inject.session = __perf_session__new(&data, inject.is_pipe, + perf_data__fd(&inject.output), + &inject.tool); if (IS_ERR(inject.session)) { ret = PTR_ERR(inject.session); goto out_close_output; -- 2.7.4