On 07/19/22 12:42, Dan Carpenter wrote:
> This code just reads from memory without caring about the data itself.
> However static checkers complain that "tmp" is never properly
> initialized. Initialize it to zero and change the name to "dummy" to
> show that we don't care about the value stored in it.
>
> Fixes: c4b6cb884011 ("selftests/vm: add hugetlb madvise MADV_DONTNEED MADV_REMOVE test")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> tools/testing/selftests/vm/hugetlb-madvise.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
Thanks Dan!
Your analysis is correct. We do not care about the value returned, and
just want to trigger a read fault.
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
>
> diff --git a/tools/testing/selftests/vm/hugetlb-madvise.c b/tools/testing/selftests/vm/hugetlb-madvise.c
> index 6c6af40f5747..3c9943131881 100644
> --- a/tools/testing/selftests/vm/hugetlb-madvise.c
> +++ b/tools/testing/selftests/vm/hugetlb-madvise.c
> @@ -89,10 +89,11 @@ void write_fault_pages(void *addr, unsigned long nr_pages)
>
> void read_fault_pages(void *addr, unsigned long nr_pages)
> {
> - unsigned long i, tmp;
> + unsigned long dummy = 0;
> + unsigned long i;
>
> for (i = 0; i < nr_pages; i++)
> - tmp += *((unsigned long *)(addr + (i * huge_page_size)));
When I originally wrote this, something must have complained if written as:
tmp = *((unsigned long *)(addr + (i * huge_page_size)));
changing to += eliminated that complaint, but caused this one. Happy
with your changes, but if there is an even better way to write this, I am
happy to change it.
--
Mike Kravetz
> + dummy += *((unsigned long *)(addr + (i * huge_page_size)));
> }
>
> int main(int argc, char **argv)
> --
> 2.35.1
>
