perf trace: Filter own pid to avoid a feedback look in 'perf trace record -a'

When doing a system wide 'perf trace record' we need, just like in 'perf
trace' live mode, to filter out perf trace's own pid, so set up a
tracepoint filter for the raw_syscalls tracepoints right after adding
them to the argv array that is set up to then call cmd_record().

Reported-by: Andi Kleen <ak@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-uysx5w8f2y5ndoln5cq370tv@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 467e18e6f8ec3cfadd88e2474094aed96f4056bd..cdee22dac2b3220aca8948c0b857b54e1378b9ca 100644 (file)
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2796,21 +2796,23 @@ static int trace__record(struct trace *trace, int argc, const char **argv)
                "-m", "1024",
                "-c", "1",
        };
-
+       pid_t pid = getpid();
+       char *filter = asprintf__tp_filter_pids(1, &pid);
        const char * const sc_args[] = { "-e", };
        unsigned int sc_args_nr = ARRAY_SIZE(sc_args);
        const char * const majpf_args[] = { "-e", "major-faults" };
        unsigned int majpf_args_nr = ARRAY_SIZE(majpf_args);
        const char * const minpf_args[] = { "-e", "minor-faults" };
        unsigned int minpf_args_nr = ARRAY_SIZE(minpf_args);
+       int err = -1;
 
-       /* +1 is for the event string below */
-       rec_argc = ARRAY_SIZE(record_args) + sc_args_nr + 1 +
+       /* +3 is for the event string below and the pid filter */
+       rec_argc = ARRAY_SIZE(record_args) + sc_args_nr + 3 +
                majpf_args_nr + minpf_args_nr + argc;
        rec_argv = calloc(rec_argc + 1, sizeof(char *));
 
-       if (rec_argv == NULL)
-               return -ENOMEM;
+       if (rec_argv == NULL || filter == NULL)
+               goto out_free;
 
        j = 0;
        for (i = 0; i < ARRAY_SIZE(record_args); i++)
@@ -2827,11 +2829,13 @@ static int trace__record(struct trace *trace, int argc, const char **argv)
                        rec_argv[j++] = "syscalls:sys_enter,syscalls:sys_exit";
                else {
                        pr_err("Neither raw_syscalls nor syscalls events exist.\n");
-                       free(rec_argv);
-                       return -1;
+                       goto out_free;
                }
        }
 
+       rec_argv[j++] = "--filter";
+       rec_argv[j++] = filter;
+
        if (trace->trace_pgfaults & TRACE_PFMAJ)
                for (i = 0; i < majpf_args_nr; i++)
                        rec_argv[j++] = majpf_args[i];
@@ -2843,7 +2847,11 @@ static int trace__record(struct trace *trace, int argc, const char **argv)
        for (i = 0; i < (unsigned int)argc; i++)
                rec_argv[j++] = argv[i];
 
-       return cmd_record(j, rec_argv);
+       err = cmd_record(j, rec_argv);
+out_free:
+       free(filter);
+       free(rec_argv);
+       return err;
 }
 
 static size_t trace__fprintf_thread_summary(struct trace *trace, FILE *fp);