From: Björn Töpel <>

This reverts commit 36e0f12bbfd3016f495904b35e41c5711707509f.

The reverted commit adds a WARN to check against NULL entries in the
mem_id_ht rhashtable. Any kernel path implementing the XDP (generic or
driver) fast path is required to make a paired
xdp_rxq_info_reg/xdp_rxq_info_unreg call for proper function. In
addition, a driver using a different allocation scheme than the
default MEM_TYPE_PAGE_SHARED is required to additionally call

For MEM_TYPE_ZERO_COPY, an xdp_rxq_info_reg_mem_model call ensures
that the mem_id_ht rhashtable has a properly inserted allocator id. If
not, this would be a driver bug. A NULL pointer kernel OOPS is
preferred to the WARN.

Suggested-by: Jesper Dangaard Brouer <>
Signed-off-by: Björn Töpel <>
 net/core/xdp.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/core/xdp.c b/net/core/xdp.c
index 6771f1855b96..9d1f22072d5d 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -345,8 +345,7 @@ static void __xdp_return(void *data, struct xdp_mem_info 
*mem, bool napi_direct,
                /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */
                xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
-               if (!WARN_ON_ONCE(!xa))
-                       xa->zc_alloc->free(xa->zc_alloc, handle);
+               xa->zc_alloc->free(xa->zc_alloc, handle);
                /* Not possible, checked in xdp_rxq_info_reg_mem_model() */

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