On 28 May 2025, at 7:31, Dev Jain wrote:
> Suppose xas is pointing somewhere near the end of the multi-entry batch.
> Then it may happen that the computed slot already falls beyond the batch,
> thus breaking the loop due to !xa_is_sibling(), and computing the wrong
> order. Thus ensure that the caller is aware of this by triggering a BUG
> when the entry is a sibling entry.
Is it possible to add a test case in lib/test_xarray.c for this?
You can compile the tests with “make -C tools/testing/radix-tree”
and run “./tools/testing/radix-tree/xarray”.
>
> This patch is motivated by code inspection and not a real bug report.
>
> Signed-off-by: Dev Jain <dev.jain@xxxxxxx>
> ---
> The patch applies on 6.15 kernel.
>
> lib/xarray.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/lib/xarray.c b/lib/xarray.c
> index 9644b18af18d..0f699766c24f 100644
> --- a/lib/xarray.c
> +++ b/lib/xarray.c
> @@ -1917,6 +1917,8 @@ int xas_get_order(struct xa_state *xas)
> if (!xas->xa_node)
> return 0;
>
> + XA_NODE_BUG_ON(xas->xa_node, xa_is_sibling(xa_entry(xas->xa,
> + xas->xa_node, xas->xa_offset)));
> for (;;) {
> unsigned int slot = xas->xa_offset + (1 << order);
>
> --
> 2.30.2
Best Regards,
Yan, Zi
