af_packet: TPACKET_V3: fix fill status rwlock imbalance (88fd1cb8) · Commits · 戴 / test

After @blk_fill_in_prog_lock is acquired there is an early out vnet situation that can occur. In that case, the rwlock needs to be released. Also, since @blk_fill_in_prog_lock is only acquired when @tp_version is exactly TPACKET_V3, only release it on that exact condition as well. And finally, add sparse annotation so that it is clearer that prb_fill_curr_block() and prb_clear_blk_fill_status() are acquiring and releasing @blk_fill_in_prog_lock, respectively. sparse is still unable to understand the balance, but the warnings are now on a higher level that make more sense. Fixes: ("af_packet: TPACKET_V3: replace busy-wait loop") Signed-off-by:

John Ogness <john.ogness@linutronix.de> Reported-by:

kernel test robot <lkp@intel.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/packet/af_packet.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -941,6 +941,7 @@ static int prb_queue_frozen(struct tpacket_kbdq_core *pkc)
		}

		static void prb_clear_blk_fill_status(struct packet_ring_buffer *rb)
		__releases(&pkc->blk_fill_in_prog_lock)
		{
		struct tpacket_kbdq_core *pkc = GET_PBDQC_FROM_RB(rb);

		@@ -989,6 +990,7 @@ static void prb_fill_curr_block(char *curr,
		struct tpacket_kbdq_core *pkc,
		struct tpacket_block_desc *pbd,
		unsigned int len)
		__acquires(&pkc->blk_fill_in_prog_lock)
		{
		struct tpacket3_hdr *ppd;

		@@ -2286,8 +2288,11 @@ static int tpacket_rcv(struct sk_buff skb, struct net_device dev,
		if (do_vnet &&
		virtio_net_hdr_from_skb(skb, h.raw + macoff -
		sizeof(struct virtio_net_hdr),
		vio_le(), true, 0))
		vio_le(), true, 0)) {
		if (po->tp_version == TPACKET_V3)
		prb_clear_blk_fill_status(&po->rx_ring);
		goto drop_n_account;
		}

		if (po->tp_version <= TPACKET_V2) {
		packet_increment_rx_head(po, &po->rx_ring);
		@@ -2393,7 +2398,7 @@ static int tpacket_rcv(struct sk_buff skb, struct net_device dev,
		__clear_bit(slot_id, po->rx_ring.rx_owner_map);
		spin_unlock(&sk->sk_receive_queue.lock);
		sk->sk_data_ready(sk);
		} else {
		} else if (po->tp_version == TPACKET_V3) {
		prb_clear_blk_fill_status(&po->rx_ring);
		}

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