diff --git a/usr.sbin/pmcstat/pmcstat.c b/usr.sbin/pmcstat/pmcstat.c
--- a/usr.sbin/pmcstat/pmcstat.c
+++ b/usr.sbin/pmcstat/pmcstat.c
@@ -452,6 +452,7 @@
 	int do_callchain, do_descendants, do_logproccsw, do_logprocexit;
 	int do_print, do_read, do_listcounters, do_descr, domains;
 	int do_userspace, i;
+	int exitcode;
 	size_t len;
 	int graphdepth;
 	int pipefd[2], rfd;
@@ -480,6 +481,7 @@
 	do_logprocexit          = 0;
 	do_listcounters         = 0;
 	domains			= 0;
+	exitcode		= EX_OK;
 	use_cumulative_counts   = 0;
 	graphfilename		= "-";
 	args.pa_required	= 0;
@@ -1420,13 +1422,21 @@
 				 * ourselves.
 				 */
 				(void) wait(&c);
+				exitcode = EX_IOERR;
 				runstate = PMCSTAT_FINISHED;
 			} else if (kev.ident == SIGIO) {
+				struct pmcstat_target *pt;
 				/*
 				 * We get a SIGIO if a PMC loses all
 				 * of its targets, or if logfile
 				 * writes encounter an error.
 				 */
+				assert(args.pa_flags & FLAG_HAS_COMMANDLINE);
+				pt = SLIST_FIRST(&args.pa_targets);
+				if (wait4(pt->pt_pid, &c, 0, NULL) <= 0 ||
+				    !WIFEXITED(c) || WEXITSTATUS(c) != 0) {
+					exitcode = EX_IOERR;
+				}
 				runstate = pmcstat_close_log(&args);
 				do_print = 1; /* print PMCs at exit */
 			} else if (kev.ident == SIGINT) {
@@ -1516,5 +1526,5 @@
 			    );
 	}
 
-	exit(EX_OK);
+	exit(exitcode);
 }