[PATCH 4.16 091/161] staging: fsl-dpaa2/eth: Fix incorrect kfree

From: Greg Kroah-Hartman
Date: Thu May 24 2018 - 05:29:17 EST


4.16-stable review patch. If anyone has any objections, please let me know.

------------------

From: Ioana Radulescu <ruxandra.radulescu@xxxxxxx>

[ Upstream commit 6a9bbe53db9a5aa0be9788aa8a2c250dee55444b ]

Use netdev_alloc_frag() instead of kmalloc to allocate space for
the S/G table of egress multi-buffer frames.

This fixes a bug where an unaligned pointer received from the
allocator would be overwritten with the 64B aligned value,
leading to a wrong address being later passed to kfree.

Signed-off-by: Ioana Radulescu <ruxandra.radulescu@xxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/fsl-dpaa2/ethernet/dpaa2-eth.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

--- a/drivers/staging/fsl-dpaa2/ethernet/dpaa2-eth.c
+++ b/drivers/staging/fsl-dpaa2/ethernet/dpaa2-eth.c
@@ -374,12 +374,14 @@ static int build_sg_fd(struct dpaa2_eth_
/* Prepare the HW SGT structure */
sgt_buf_size = priv->tx_data_offset +
sizeof(struct dpaa2_sg_entry) * (1 + num_dma_bufs);
- sgt_buf = kzalloc(sgt_buf_size + DPAA2_ETH_TX_BUF_ALIGN, GFP_ATOMIC);
+ sgt_buf = netdev_alloc_frag(sgt_buf_size + DPAA2_ETH_TX_BUF_ALIGN);
if (unlikely(!sgt_buf)) {
err = -ENOMEM;
goto sgt_buf_alloc_failed;
}
sgt_buf = PTR_ALIGN(sgt_buf, DPAA2_ETH_TX_BUF_ALIGN);
+ memset(sgt_buf, 0, sgt_buf_size);
+
sgt = (struct dpaa2_sg_entry *)(sgt_buf + priv->tx_data_offset);

/* Fill in the HW SGT structure.
@@ -421,7 +423,7 @@ static int build_sg_fd(struct dpaa2_eth_
return 0;

dma_map_single_failed:
- kfree(sgt_buf);
+ skb_free_frag(sgt_buf);
sgt_buf_alloc_failed:
dma_unmap_sg(dev, scl, num_sg, DMA_BIDIRECTIONAL);
dma_map_sg_failed:
@@ -525,9 +527,9 @@ static void free_tx_fd(const struct dpaa
return;
}

- /* Free SGT buffer kmalloc'ed on tx */
+ /* Free SGT buffer allocated on tx */
if (fd_format != dpaa2_fd_single)
- kfree(skbh);
+ skb_free_frag(skbh);

/* Move on with skb release */
dev_kfree_skb(skb);