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octeon_ep: Add SKB allocation failures handling in __octep_oq_process_rx()

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[ Upstream commit eb592008f7 ]

build_skb() returns NULL in case of a memory allocation failure so handle
it inside __octep_oq_process_rx() to avoid NULL pointer dereference.

__octep_oq_process_rx() is called during NAPI polling by the driver. If
skb allocation fails, keep on pulling packets out of the Rx DMA queue: we
shouldn't break the polling immediately and thus falsely indicate to the
octep_napi_poll() that the Rx pressure is going down. As there is no
associated skb in this case, don't process the packets and don't push them
up the network stack - they are skipped.

Helper function is implemented to unmmap/flush all the fragment buffers
used by the dropped packet. 'alloc_failures' counter is incremented to
mark the skb allocation error in driver statistics.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 37d79d0596 ("octeon_ep: add Tx/Rx processing and interrupt support")
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Aleksandr Mishin 2024-10-17 13:06:51 +03:00 committed by Greg Kroah-Hartman
parent e71146ff37
commit c2d2dc4f88
1 changed files with 27 additions and 0 deletions
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27
drivers/net/ethernet/marvell/octeon_ep/octep_rx.c
View File

@ -360,6 +360,27 @@ static void octep_oq_next_pkt(struct octep_oq *oq,
*read_idx = 0;
}
/**
* octep_oq_drop_rx() - Free the resources associated with a packet.
*
* @oq: Octeon Rx queue data structure.
* @buff_info: Current packet buffer info.
* @read_idx: Current packet index in the ring.
* @desc_used: Current packet descriptor number.
*
*/
static void octep_oq_drop_rx(struct octep_oq *oq,
struct octep_rx_buffer *buff_info,
u32 *read_idx, u32 *desc_used)
{
int data_len = buff_info->len - oq->max_single_buffer_size;
while (data_len > 0) {
octep_oq_next_pkt(oq, buff_info, read_idx, desc_used);
data_len -= oq->buffer_size;
};
}
/**
* __octep_oq_process_rx() - Process hardware Rx queue and push to stack.
*
@ -415,6 +436,12 @@ static int __octep_oq_process_rx(struct octep_device *oct,
octep_oq_next_pkt(oq, buff_info, &read_idx, &desc_used);
skb = build_skb((void *)resp_hw, PAGE_SIZE);
if (!skb) {
octep_oq_drop_rx(oq, buff_info,
&read_idx, &desc_used);
oq->stats.alloc_failures++;
continue;
}
skb_reserve(skb, data_offset);
rx_bytes += buff_info->len;