From: Taehee Yoo <ap420073@gmail.com>
Date: Thu, 26 Jul 2018 23:17:03 +0900
Subject: xdp: add NULL pointer check in __xdp_return()
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Patch-mainline: v4.18-rc8
Git-commit: 36e0f12bbfd3016f495904b35e41c5711707509f
References: bsc#1109837

rhashtable_lookup() can return NULL. so that NULL pointer
check routine should be added.

Fixes: 02b55e5657c3 ("xdp: add MEM_TYPE_ZERO_COPY")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/core/xdp.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -345,7 +345,8 @@ static void __xdp_return(void *data, str
 		rcu_read_lock();
 		/* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */
 		xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
-		xa->zc_alloc->free(xa->zc_alloc, handle);
+		if (!WARN_ON_ONCE(!xa))
+			xa->zc_alloc->free(xa->zc_alloc, handle);
 		rcu_read_unlock();
 	default:
 		/* Not possible, checked in xdp_rxq_info_reg_mem_model() */