From: Dan Carpenter <dan.carpenter@oracle.com>
To: mw@semihalf.com
Cc: netdev@vger.kernel.org
Subject: re: net: mvpp2: fix missing DMA region unmap in egress processing
Date: Tue, 8 Dec 2015 22:38:46 +0300 [thread overview]
Message-ID: <20151208193846.GA25726@mwanda> (raw)
Hello Marcin Wojtas,
The patch e864b4c7b184: "net: mvpp2: fix missing DMA region unmap in
egress processing" from Dec 3, 2015, leads to the following static
checker warning:
drivers/net/ethernet/marvell/mvpp2.c:4414 mvpp2_txq_bufs_free()
warn: variable dereferenced before check 'skb' (see line 4412)
drivers/net/ethernet/marvell/mvpp2.c
4399 static void mvpp2_txq_bufs_free(struct mvpp2_port *port,
4400 struct mvpp2_tx_queue *txq,
4401 struct mvpp2_txq_pcpu *txq_pcpu, int num)
4402 {
4403 int i;
4404
4405 for (i = 0; i < num; i++) {
4406 dma_addr_t buf_phys_addr =
4407 txq_pcpu->tx_buffs[txq_pcpu->txq_get_index];
4408 struct sk_buff *skb = txq_pcpu->tx_skb[txq_pcpu->txq_get_index];
4409
4410 mvpp2_txq_inc_get(txq_pcpu);
4411
4412 dma_unmap_single(port->dev->dev.parent, buf_phys_addr,
4413 skb_headlen(skb), DMA_TO_DEVICE);
^^^^^^^^^^^^^^^^
Dereference inside function.
4414 if (!skb)
^^^^^
Check too late. There is no way that patch can be fix a bug, the best
case is that it does nothing or maybe it adds an oops...
4415 continue;
4416 dev_kfree_skb_any(skb);
4417 }
4418 }
regards,
dan carpenter
reply other threads:[~2015-12-08 19:39 UTC|newest]
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