[PATCH] Fix division by zero in deviance calculation

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/stat.c b/stat.c
index b4facc7eab4da21a71ff7f343f7e2f264ab9ea40..6e55925b1cf288ebadc565a4d4c506248ed22b9e 100644 (file)
--- a/stat.c
+++ b/stat.c
@@ -281,8 +281,12 @@ static int calc_lat(struct io_stat *is, unsigned long *min, unsigned long *max,
 
        n = (double) is->samples;
        *mean = (double) is->val / n;
 
        n = (double) is->samples;
        *mean = (double) is->val / n;

-       *dev = sqrt(((double) is->val_sq - (*mean * *mean) / n) / (n - 1));
+       *dev = 0;
+
+       if (n <= 1)
+               return 1;

 
 

+       *dev = sqrt(((double) is->val_sq - (*mean * *mean) / n) / (n - 1));

        return 1;
 }
 
        return 1;
 }