From 372a4ffae4c3ea164a0ef57ca02b7e75b5b24011 Mon Sep 17 00:00:00 2001 From: Maxim Mikityanskiy Date: Mon, 16 Sep 2019 14:54:20 +0300 Subject: net/mlx5e: Fix handling of compressed CQEs in case of low NAPI budget [ 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 Signed-off-by: Saeed Mahameed Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c index ac6e586d403d..fb139f8b9acf 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c @@ -1367,8 +1367,11 @@ int mlx5e_poll_rx_cq(struct mlx5e_cq *cq, int budget) if (unlikely(!test_bit(MLX5E_RQ_STATE_ENABLED, &rq->state))) return 0; - if (rq->cqd.left) + if (rq->cqd.left) { work_done += mlx5e_decompress_cqes_cont(rq, cqwq, 0, budget); + if (rq->cqd.left || work_done >= budget) + goto out; + } cqe = mlx5_cqwq_get_cqe(cqwq); if (!cqe) { -- cgit v1.2.3