tools/power turbostat: Fix trailing '\n' parsing

[ Upstream commit fed8511cc8996989178823052dc0200643e1389a ]

parse_cpu_string() parses the string input either from command line or
from /sys/fs/cgroup/cpuset.cpus.effective to get a list of CPUs that
turbostat can run with.

The cpu string returned by /sys/fs/cgroup/cpuset.cpus.effective contains
a trailing '\n', but strtoul() fails to treat this as an error.

That says, for the code below
	val = ("\n", NULL, 10);
val returns 0, and errno is also not set.

As a result, CPU0 is erroneously considered as allowed CPU and this
causes failures when turbostat tries to run on CPU0.

 get_counters: Could not migrate to CPU 0
 ...
 turbostat: re-initialized with num_cpus 8, allowed_cpus 5
 get_counters: Could not migrate to CPU 0

Add a check to return immediately if '\n' or '\0' is detected.

Fixes: 8c3dd2c9e542 ("tools/power/turbostat: Abstrct function for parsing cpu string")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 089220aaa5c9291b5e0432ec1d0fa9b3f44b3e1a..aa9200319d0eafa7de394f91ad5b1113317f1749 100644 (file)
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -5385,6 +5385,9 @@ static int parse_cpu_str(char *cpu_str, cpu_set_t *cpu_set, int cpu_set_size)
                if (*next == '-')       /* no negative cpu numbers */
                        return 1;
 
+               if (*next == '\0' || *next == '\n')
+                       break;
+
                start = strtoul(next, &next, 10);
 
                if (start >= CPU_SUBSET_MAXCPUS)