On Tue, Dec 20, 2022 at 07:27:04PM +0100, Uladzislau Rezki (Sony) wrote:
> Currently a vm_unmap_ram() functions triggers a BUG() if an area
> is not found. Replace it by the WARN_ON_ONCE() error message and
> keep machine alive instead of stopping it.
>
> The worst case is a memory leaking.
>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
> ---
> mm/vmalloc.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 0fc38c36e0df..e05a0dc79ac5 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2255,10 +2255,12 @@ void vm_unmap_ram(const void *mem, unsigned int count)
> }
>
> va = find_unlink_vmap_area(addr);
> - BUG_ON(!va);
> - debug_check_no_locks_freed((void *)va->va_start,
> - (va->va_end - va->va_start));
> - free_unmap_vmap_area(va);
> +
> + if (!WARN_ON_ONCE(!va)) {
> + debug_check_no_locks_freed((void *)va->va_start,
> + (va->va_end - va->va_start));
> + free_unmap_vmap_area(va);
> + }
> }
> EXPORT_SYMBOL(vm_unmap_ram);
>
> --
> 2.30.2
>
Absolutely in favour of this in principle (BUG_ON() is something we should
resort to in only the direst of circumstances), one small nit - perhaps it'd be
neater to simply make this a guard clause? E.g.:-
if (!WARN_ON_ONCE(!va))
return;
...
