net: Fix a data-race around gro_normal_batch.

[ Upstream commit 8db24af3f02ebdbf302196006ebb270c4c3a2706 ]

While reading gro_normal_batch, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 323ebb61e32b ("net: use listified RX for handling GRO_NORMAL skbs")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/net/gro.h b/include/net/gro.h
index 867656b0739c0985cae50d1aaf2e1d70bb1c80ed..24003dea8fa4de93edcc10ed6a02a80864732680 100644 (file)
--- a/include/net/gro.h
+++ b/include/net/gro.h
@@ -439,7 +439,7 @@ static inline void gro_normal_one(struct napi_struct *napi, struct sk_buff *skb,
 {
        list_add_tail(&skb->list, &napi->rx_list);
        napi->rx_count += segs;
-       if (napi->rx_count >= gro_normal_batch)
+       if (napi->rx_count >= READ_ONCE(gro_normal_batch))
                gro_normal_list(napi);
 }