[PATCH 4.9 098/171] net: qlogic: Fix error paths in ql_alloc_large_buffers()

From: Greg Kroah-Hartman
Date: Thu Jan 02 2020 - 17:31:34 EST

From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>

[ Upstream commit cad46039e4c99812db067c8ac22a864960e7acc4 ]

ql_alloc_large_buffers() has the usual RX buffer allocation
loop where it allocates skbs and maps them for DMA. It also
treats failure as a fatal error.

There are (at least) three bugs in the error paths:

1. ql_free_large_buffers() assumes that the lrg_buf[] entry for the
first buffer that couldn't be allocated will have .skb == NULL.
But the qla_buf[] array is not zero-initialised.

2. ql_free_large_buffers() DMA-unmaps all skbs in lrg_buf[]. This is
incorrect for the last allocated skb, if DMA mapping failed.

3. Commit 1acb8f2a7a9f ("net: qlogic: Fix memory leak in
ql_alloc_large_buffers") added a direct call to dev_kfree_skb_any()
after the skb is recorded in lrg_buf[], so ql_free_large_buffers()
will double-free it.

The bugs are somewhat inter-twined, so fix them all at once:

* Clear each entry in qla_buf[] before attempting to allocate
an skb for it. This goes half-way to fixing bug 1.
* Set the .skb field only after the skb is DMA-mapped. This
fixes the rest.

Fixes: 1357bfcf7106 ("qla3xxx: Dynamically size the rx buffer queue ...")
Fixes: 0f8ab89e825f ("qla3xxx: Check return code from pci_map_single() ...")
Fixes: 1acb8f2a7a9f ("net: qlogic: Fix memory leak in ql_alloc_large_buffers")
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/net/ethernet/qlogic/qla3xxx.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/qlogic/qla3xxx.c
+++ b/drivers/net/ethernet/qlogic/qla3xxx.c
@@ -2752,6 +2752,9 @@ static int ql_alloc_large_buffers(struct
int err;

for (i = 0; i < qdev->num_large_buffers; i++) {
+ lrg_buf_cb = &qdev->lrg_buf[i];
+ memset(lrg_buf_cb, 0, sizeof(struct ql_rcv_buf_cb));
skb = netdev_alloc_skb(qdev->ndev,
if (unlikely(!skb)) {
@@ -2762,11 +2765,7 @@ static int ql_alloc_large_buffers(struct
return -ENOMEM;
} else {
- lrg_buf_cb = &qdev->lrg_buf[i];
- memset(lrg_buf_cb, 0, sizeof(struct ql_rcv_buf_cb));
lrg_buf_cb->index = i;
- lrg_buf_cb->skb = skb;
* We save some space to copy the ethhdr from first
* buffer
@@ -2788,6 +2787,7 @@ static int ql_alloc_large_buffers(struct
return -ENOMEM;

+ lrg_buf_cb->skb = skb;
dma_unmap_addr_set(lrg_buf_cb, mapaddr, map);
dma_unmap_len_set(lrg_buf_cb, maplen,
qdev->lrg_buffer_len -