Re: [dpdk-dev] [PATCH] usertools: check 0-division with hugepage size

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 11-Feb-21 10:05 PM, Thomas Monjalon wrote:
> The default page size can be None, and the page size from user request
> can be 0 kB if lower than 1024. In these cases, a division will fail.
> In order to avoid a Python exception, the page size is checked
> and an error message "Invalid page size" is printed.
> 
> A similar error message is printed in set_hugepages()
> if the size is not supported, except at this stage the message can be
> completed with "Valid page sizes".
> Unfortunately the first check is too early to print such information.
> 
> A third error message can be printed in a different place (get_memsize)
> in case of a format issue, e.g. a negative size.
> The function get_memsize() is also used for total requested size,
> so the error message "not a valid page size" was potentially wrong.
> This message is replaced with the more general "is not a valid size".
> 
> Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> ---
>   usertools/dpdk-hugepages.py | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/usertools/dpdk-hugepages.py b/usertools/dpdk-hugepages.py
> index fb368b6933..c1f2549ec0 100755
> --- a/usertools/dpdk-hugepages.py
> +++ b/usertools/dpdk-hugepages.py
> @@ -29,7 +29,7 @@ def get_memsize(arg):
>       '''Convert memory size with suffix to kB'''
>       match = re.match(r'(\d+)([' + BINARY_PREFIX + r']?)$', arg.upper())
>       if match is None:
> -        sys.exit('{} is not a valid page size'.format(arg))
> +        sys.exit('{} is not a valid size'.format(arg))
>       num = float(match.group(1))
>       suffix = match.group(2)
>       if suffix == "":
> @@ -254,6 +254,8 @@ def main():
>           pagesize_kb = get_memsize(args.pagesize)
>       else:
>           pagesize_kb = default_pagesize()
> +    if pagesize_kb is None or pagesize_kb == 0:
> +        sys.exit("Invalid page size: {}kB".format(pagesize_kb))

Both None and 0 evaluate to False for boolean comparisons, so you can 
replace it with:

if not pagesize_kb:
    sys.exit(...)

>   
>       if args.clear:
>           clear_pages()
> 


-- 
Thanks,
Anatoly