From: Len Brown <len.brown@intel.com>
Date: Thu, 1 Oct 2020 00:58:15 +0000 (-0400)
Subject: tools/power turbostat: harden against cpu hotplug
X-Git-Tag: microblaze-v5.12~399^2~2
X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=3d7772ea5602b88c7c7f0a50d512171a2eed6659;p=linux-2.6-microblaze.git

tools/power turbostat: harden against cpu hotplug

turbostat tends to get confused when CPUs are added and removed
while it is running.

There are races, such as checking the current cpu, and then
reading a sysfs file that depends on that cpu number.

Close the two issues that seem to come up the most.
First, there is an infinite reset loop detector --
change that to allow more resets before giving up.
Secondly, one of those file reads didn't really need
to exit the program on failure...

Signed-off-by: Len Brown <len.brown@intel.com>
---

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 4122468fb73b..74d2fc6fc78a 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -1894,7 +1894,7 @@ int get_counters(struct thread_data *t, struct core_data *c, struct pkg_data *p)
 	int i;
 
 	if (cpu_migrate(cpu)) {
-		fprintf(outf, "Could not migrate to CPU %d\n", cpu);
+		fprintf(outf, "get_counters: Could not migrate to CPU %d\n", cpu);
 		return -1;
 	}
 
@@ -2764,7 +2764,12 @@ int get_thread_siblings(struct cpu_topology *thiscpu)
 
 	sprintf(path,
 		"/sys/devices/system/cpu/cpu%d/topology/thread_siblings", cpu);
-	filep = fopen_or_die(path, "r");
+	filep = fopen(path, "r");
+
+	if (!filep) {
+		warnx("%s: open failed", path);
+		return -1;
+	}
 	do {
 		offset -= BITMASK_SIZE;
 		if (fscanf(filep, "%lx%c", &map, &character) != 2)
@@ -2877,7 +2882,7 @@ void re_initialize(void)
 {
 	free_all_buffers();
 	setup_all_buffers();
-	printf("turbostat: re-initialized with num_cpus %d\n", topo.num_cpus);
+	fprintf(outf, "turbostat: re-initialized with num_cpus %d\n", topo.num_cpus);
 }
 
 void set_max_cpu_num(void)
@@ -3331,7 +3336,7 @@ restart:
 	if (retval < -1) {
 		exit(retval);
 	} else if (retval == -1) {
-		if (restarted > 1) {
+		if (restarted > 10) {
 			exit(retval);
 		}
 		re_initialize();
@@ -3926,7 +3931,7 @@ int print_epb(struct thread_data *t, struct core_data *c, struct pkg_data *p)
 		return 0;
 
 	if (cpu_migrate(cpu)) {
-		fprintf(outf, "Could not migrate to CPU %d\n", cpu);
+		fprintf(outf, "print_epb: Could not migrate to CPU %d\n", cpu);
 		return -1;
 	}
 
@@ -3970,7 +3975,7 @@ int print_hwp(struct thread_data *t, struct core_data *c, struct pkg_data *p)
 		return 0;
 
 	if (cpu_migrate(cpu)) {
-		fprintf(outf, "Could not migrate to CPU %d\n", cpu);
+		fprintf(outf, "print_hwp: Could not migrate to CPU %d\n", cpu);
 		return -1;
 	}
 
@@ -4058,7 +4063,7 @@ int print_perf_limit(struct thread_data *t, struct core_data *c, struct pkg_data
 		return 0;
 
 	if (cpu_migrate(cpu)) {
-		fprintf(outf, "Could not migrate to CPU %d\n", cpu);
+		fprintf(outf, "print_perf_limit: Could not migrate to CPU %d\n", cpu);
 		return -1;
 	}
 
@@ -4439,7 +4444,7 @@ int print_thermal(struct thread_data *t, struct core_data *c, struct pkg_data *p
 		return 0;
 
 	if (cpu_migrate(cpu)) {
-		fprintf(outf, "Could not migrate to CPU %d\n", cpu);
+		fprintf(outf, "print_thermal: Could not migrate to CPU %d\n", cpu);
 		return -1;
 	}
 
@@ -4511,7 +4516,7 @@ int print_rapl(struct thread_data *t, struct core_data *c, struct pkg_data *p)
 
 	cpu = t->cpu_id;
 	if (cpu_migrate(cpu)) {
-		fprintf(outf, "Could not migrate to CPU %d\n", cpu);
+		fprintf(outf, "print_rapl: Could not migrate to CPU %d\n", cpu);
 		return -1;
 	}