On Mon, Jun 17, 2019 at 02:14:11PM +0200, Arnd Bergmann wrote:
> gcc points out some obviously broken code in linux-next
>
> mm/vmalloc.c: In function 'pcpu_get_vm_areas':
> mm/vmalloc.c:991:4: error: 'lva' may be used uninitialized in this function
> [-Werror=maybe-uninitialized]
> insert_vmap_area_augment(lva, &va->rb_node,
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> &free_vmap_area_root, &free_vmap_area_list);
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> mm/vmalloc.c:916:20: note: 'lva' was declared here
> struct vmap_area *lva;
> ^~~
>
> Remove the obviously broken code. This is almost certainly
> not the correct solution, but it's what I have applied locally
> to get a clean build again.
>
> Please fix this properly.
>
> Fixes: 68ad4a330433 ("mm/vmalloc.c: keep track of free blocks for vmap
> allocation")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> mm/vmalloc.c | 7 +------
> 1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index a9213fc3802d..bfcf0124a773 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -984,14 +984,9 @@ adjust_va_to_fit_type(struct vmap_area *va,
> return -1;
> }
>
> - if (type != FL_FIT_TYPE) {
> + if (type == FL_FIT_TYPE)
> augment_tree_propagate_from(va);
>
> - if (type == NE_FIT_TYPE)
> - insert_vmap_area_augment(lva, &va->rb_node,
> - &free_vmap_area_root, &free_vmap_area_list);
> - }
> -
> return 0;
> }
>
> --
> 2.20.0
>
Please do not apply this. It will just break everything. As Roman
pointed we can just set lva = NULL; in the beginning to make GCC happy.
For some reason GCC decides that it can be used uninitialized, but that
is not true.
--
Vlad Rezki
