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af_packet: TPACKET_V3: fix fill status rwlock imbalance

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[ Upstream commit 88fd1cb80daa20af063bce81e1fad14e945a8dc4 ]

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: 632ca50f2cbd ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
John Ogness 2020-08-13 21:45:25 +02:06 committed by Greg Kroah-Hartman
parent 7ea71a7be5
commit ff00ef9aac
1 changed files with 7 additions and 2 deletions
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9
net/packet/af_packet.c
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@ -949,6 +949,7 @@ 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);
atomic_dec(&pkc->blk_fill_in_prog);
@ -996,6 +997,7 @@ 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;
@ -2272,8 +2274,11 @@ 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);
@ -2379,7 +2384,7 @@ 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);
}