From: Maxim Mikityanskiy maximmi@mellanox.com
[ Upstream commit 9df86bdb6746d7fcfc2fda715f7a7c3d0ddb2654 ]
When CQE compression is enabled, compressed CQEs use the following structure: a title is followed by one or many blocks, each containing 8 mini CQEs (except the last, which may contain fewer mini CQEs).
Due to NAPI budget restriction, a complete structure is not always parsed in one NAPI run, and some blocks with mini CQEs may be deferred to the next NAPI poll call - we have the mlx5e_decompress_cqes_cont call in the beginning of mlx5e_poll_rx_cq. However, if the budget is extremely low, some blocks may be left even after that, but the code that follows the mlx5e_decompress_cqes_cont call doesn't check it and assumes that a new CQE begins, which may not be the case. In such cases, random memory corruptions occur.
An extremely low NAPI budget of 8 is used when busy_poll or busy_read is active.
This commit adds a check to make sure that the previous compressed CQE has been completely parsed after mlx5e_decompress_cqes_cont, otherwise it prevents a new CQE from being fetched in the middle of a compressed CQE.
This commit fixes random crashes in __build_skb, __page_pool_put_page and other not-related-directly places, that used to happen when both CQE compression and busy_poll/busy_read were enabled.
Fixes: 7219ab34f184 ("net/mlx5e: CQE compression") Signed-off-by: Maxim Mikityanskiy maximmi@mellanox.com Signed-off-by: Saeed Mahameed saeedm@mellanox.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c @@ -1093,8 +1093,11 @@ int mlx5e_poll_rx_cq(struct mlx5e_cq *cq if (unlikely(!MLX5E_TEST_BIT(rq->state, MLX5E_RQ_STATE_ENABLED))) return 0;
- if (cq->decmprs_left) + if (cq->decmprs_left) { work_done += mlx5e_decompress_cqes_cont(rq, cq, 0, budget); + if (cq->decmprs_left || work_done >= budget) + goto out; + }
cqe = mlx5_cqwq_get_cqe(&cq->wq); if (!cqe) {