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ice: add extra check for null Rx descriptor

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In the case where the hardware gives us a null Rx descriptor, it is
theoretically possible that we could call one of our skb-construction
functions with no data pointer, which would cause a panic.

In real life, this will never happen - we only get null RX
descriptors as the final descriptor in a chain of otherwise-valid
descriptors. When this happens, the skb will be extant and we'll just
call ice_add_rx_frag(), which can deal with empty data buffers.

Unfortunately, Coverity does not have intimate knowledge of our
hardware, so we must add a check here.

Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Mitch Williams 2019-12-12 03:13:05 -08:00 committed by Jeff Kirsher
parent ac614b13fe
commit 1f45ebe0d8
1 changed files with 8 additions and 5 deletions
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13
drivers/net/ethernet/intel/ice/ice_txrx.c
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@ -1071,13 +1071,16 @@ static int ice_clean_rx_irq(struct ice_ring *rx_ring, int budget)
ice_put_rx_buf(rx_ring, rx_buf);
continue;
construct_skb:
if (skb)
if (skb) {
ice_add_rx_frag(rx_ring, rx_buf, skb, size);
else if (ice_ring_uses_build_skb(rx_ring))
skb = ice_build_skb(rx_ring, rx_buf, &xdp);
else
} else if (likely(xdp.data)) {
if (ice_ring_uses_build_skb(rx_ring))
skb = ice_build_skb(rx_ring, rx_buf, &xdp);
else
skb = ice_construct_skb(rx_ring, rx_buf, &xdp);
} else {
skb = ice_construct_skb(rx_ring, rx_buf, &xdp);
}
/* exit if we failed to retrieve a buffer */
if (!skb) {
rx_ring->rx_stats.alloc_buf_failed++;