Open
Description
We are working on a pretty high performance system and are using the --rate option to try and constrain throughputs to 8GB/s. However we noticed that since FIO_OPT_INT is constrained to 32 bits any values over 4GB should result in an error that is detected in val_too_large().
However the code in val_too_large is failing to do this because of this line:
return (unsigned int) val > o->maxval;
which is our case tests equates to
(unsigned int) 8G > 4G
0 > 4G
= false
You can check this for yourself with something like:
./fio --debug=parse --name=parse_check --rate=8G,8G --size=16k --filename /tmp/parse.dat
Which (with a simple patch) generates:
parse 1698 dup options
parse 1698 handle_option=name, ptr=parse
parse 1698 __handle_option=name, type=OPT_STR_STORE, ptr=parse
parse 1698 handle_option=rate, ptr=8G,8G
parse 1698 __handle_option=rate, type=OPT_INT, ptr=8G,8G
parse 1698 ret=0, out=8589934592, max=4294967295
parse 1698 is_uint=1, val=8589934592, o->maxval=4294967295, (unsigned int) val=0
parse 1698 __handle_option=rate, type=OPT_INT, ptr=8G
parse 1698 ret=0, out=8589934592, max=4294967295
parse 1698 is_uint=1, val=8589934592, o->maxval=4294967295, (unsigned int) val=0
parse 1698 handle_option=size, ptr=16k
parse 1698 __handle_option=size, type=OPT_STR_VAL, ptr=16k
parse 1698 ret=0, out=16384, max=0
parse 1698 handle_option=filename, ptr=/tmp/parse.dat
parse 1698 __handle_option=filename, type=OPT_STR_STORE, ptr=/tmp/parse.dat
parse: (g=0): rw=read, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=psync, iodepth=1
parse 1698 free options
fio-3.19-52-gb2ed-dirty
Starting 1 process
Here is the patch:
diff --git a/parse.c b/parse.c
index 04b2e198..711a2ec1 100644
--- a/parse.c
+++ b/parse.c
@@ -516,6 +516,9 @@ static bool val_too_large(const struct fio_option *o, unsigned long long val,
if (!o->maxval)
return false;
+ dprint(FD_PARSE, " is_uint=%d, val=%llu, o->maxval=%llu, (unsigned int) val=%d\n",
+ is_uint, val, o->maxval, (unsigned int) val);
+
if (is_uint) {
if ((int) val < 0)
return (int) val > (int) o->maxval;
@@ -616,7 +619,7 @@ static int __handle_option(const struct fio_option *o, const char *ptr,
else
ret = check_str_bytes(tmp, &ull, data);
- dprint(FD_PARSE, " ret=%d, out=%llu\n", ret, ull);
+ dprint(FD_PARSE, " ret=%d, out=%llu, max=%llu\n", ret, ull, o->maxval);
if (ret)
break;