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perf: avoid assertion for -p option in perf stat -a

PATCH New Stephane Eranian 1 participant 1 message Jun 2, 2010 perf events

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PATCH 1/1 perf: avoid assertion for -p option in perf stat -a

It was possible to use perf stat in system-wide mode with -a and still attach to a process (-p) or thread (-t). The issue is that it is not possible to get a termination signal from the attached task, thus the command never terminates. Furthermore, passing -p -a was triggering the assertion in read_counter().

This patch fixes the issue by aborting perf stat if the parameters conflict.

tools/perf/builtin-stat.c +8 -0
index a6b4d44..a3b6a5f 100644
@@ -573,6 +573,14 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
 	else
 		nr_cpus = 1;
 
+	/*
+	 * a system-wide session cannot be delimited via an attachment
+	 * because we cannot get a termination notification.
+	 * It also triggers the assertion in read_counter()
+	 */
+	if (system_wide && (target_tid != -1 || target_pid != -1))
+		usage_with_options(stat_usage, options);
+
 	if (nr_cpus < 1)
 		usage_with_options(stat_usage, options);