From: Gerd Bayer gbayer@linux.ibm.com

stable inclusion from stable-v5.10.227 commit ca36d6c1a49b6965c86dd528a73f38bc62d9c625 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYRD9 CVE: CVE-2024-50001

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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[ 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@linux.ibm.com Reviewed-by: Zhu Yanjun yanjun.zhu@linux.dev Acked-by: Maxim Mikityanskiy maxtram95@gmail.com Signed-off-by: Saeed Mahameed saeedm@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Guo Mengqi guomengqi3@huawei.com --- drivers/net/ethernet/mellanox/mlx5/core/en_tx.c | 1 - 1 file changed, 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c index 373668068071..9b1e43ff8ae1 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c @@ -601,7 +601,6 @@ 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); }