6.8-stable review patch. If anyone has any objections, please let me know.
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From: David Arinzon darinzon@amazon.com
[ Upstream commit 36a1ca01f0452f2549420e7279c2588729bd94df ]
The patch mentioned in the `Fixes` tag removed the explicit assignment of tx_info->xdpf to NULL with the justification that there's no need to set tx_info->xdpf to NULL and tx_info->num_of_bufs to 0 in case of a mapping error. Both values won't be used once the mapping function returns an error, and their values would be overridden by the next transmitted packet.
While both values do indeed get overridden in the next transmission call, the value of tx_info->xdpf is also used to check whether a TX descriptor's transmission has been completed (i.e. a completion for it was polled).
An example scenario: 1. Mapping failed, tx_info->xdpf wasn't set to NULL 2. A VF reset occurred leading to IO resource destruction and a call to ena_free_tx_bufs() function 3. Although the descriptor whose mapping failed was freed by the transmission function, it still passes the check if (!tx_info->skb)
(skb and xdp_frame are in a union) 4. The xdp_frame associated with the descriptor is freed twice
This patch returns the assignment of NULL to tx_info->xdpf to make the cleaning function knows that the descriptor is already freed.
Fixes: 504fd6a5390c ("net: ena: fix DMA mapping function issues in XDP") Signed-off-by: Shay Agroskin shayagr@amazon.com Signed-off-by: David Arinzon darinzon@amazon.com Reviewed-by: Shannon Nelson shannon.nelson@amd.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/amazon/ena/ena_xdp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/amazon/ena/ena_xdp.c b/drivers/net/ethernet/amazon/ena/ena_xdp.c index fc1c4ef73ba32..34d73c72f7803 100644 --- a/drivers/net/ethernet/amazon/ena/ena_xdp.c +++ b/drivers/net/ethernet/amazon/ena/ena_xdp.c @@ -89,7 +89,7 @@ int ena_xdp_xmit_frame(struct ena_ring *tx_ring,
rc = ena_xdp_tx_map_frame(tx_ring, tx_info, xdpf, &ena_tx_ctx); if (unlikely(rc)) - return rc; + goto err;
ena_tx_ctx.req_id = req_id;
@@ -112,7 +112,9 @@ int ena_xdp_xmit_frame(struct ena_ring *tx_ring,
error_unmap_dma: ena_unmap_tx_buff(tx_ring, tx_info); +err: tx_info->xdpf = NULL; + return rc; }