This is a note to let you know that I've just added the patch titled
net/mlx5: Fix error path in multi-packet WQE transmit
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-mlx5-fix-error-path-in-multi-packet-wqe-transmit.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7411e2432a3b941095b38e064e6b1481f91b89bd
Author: Gerd Bayer <gbayer@xxxxxxxxxxxxx>
Date: Tue Sep 10 10:53:51 2024 +0200
net/mlx5: Fix error path in multi-packet WQE transmit
[ Upstream commit 2bcae12c795f32ddfbf8c80d1b5f1d3286341c32 ]
Remove the erroneous unmap in case no DMA mapping was established
The multi-packet WQE transmit code attempts to obtain a DMA mapping for
the skb. This could fail, e.g. under memory pressure, when the IOMMU
driver just can't allocate more memory for page tables. While the code
tries to handle this in the path below the err_unmap label it erroneously
unmaps one entry from the sq's FIFO list of active mappings. Since the
current map attempt failed this unmap is removing some random DMA mapping
that might still be required. If the PCI function now presents that IOVA,
the IOMMU may assumes a rogue DMA access and e.g. on s390 puts the PCI
function in error state.
The erroneous behavior was seen in a stress-test environment that created
memory pressure.
Fixes: 5af75c747e2a ("net/mlx5e: Enhanced TX MPWQE for SKBs")
Signed-off-by: Gerd Bayer <gbayer@xxxxxxxxxxxxx>
Reviewed-by: Zhu Yanjun <yanjun.zhu@xxxxxxxxx>
Acked-by: Maxim Mikityanskiy <maxtram95@xxxxxxxxx>
Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
index 6813279b57f89..7ec8a5ae7ea74 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
@@ -685,7 +685,6 @@ mlx5e_sq_xmit_mpwqe(struct mlx5e_txqsq *sq, struct sk_buff *skb,
return;
err_unmap:
- mlx5e_dma_unmap_wqe_err(sq, 1);
sq->stats->dropped++;
dev_kfree_skb_any(skb);
mlx5e_tx_flush(sq);
