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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Oz Shlomo , Paul Blakey , Khalid Manaa , Achiad Shochat , Jiayuan Chen , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, Leon Huang Fu References: <20260112080323.65456-1-leon.hwang@linux.dev> Content-Language: en-US From: Tariq Toukan In-Reply-To: <20260112080323.65456-1-leon.hwang@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 12/01/2026 10:03, Leon Hwang wrote: > The wqe_id from CQE contains wrap counter bits in addition to the WQE > index. Mask it with sz_m1 to prevent out-of-bounds access to the > rq->mpwqe.info[] array when wrap counter causes wqe_id to exceed RQ size. > > Without this fix, the driver crashes with NULL pointer dereference: > > BUG: kernel NULL pointer dereference, address: 0000000000000020 > RIP: 0010:mlx5e_skb_from_cqe_mpwrq_linear+0xb3/0x280 [mlx5_core] > Call Trace: > > mlx5e_handle_rx_cqe_mpwrq+0xe3/0x290 [mlx5_core] > mlx5e_poll_rx_cq+0x97/0x820 [mlx5_core] > mlx5e_napi_poll+0x110/0x820 [mlx5_core] > Hi, We do not expect out-of-bounds index, fixing it this way is not necessarily correct. Can you please elaborate on your test case, setup, and how to repro? > Fixes: dfd9e7500cd4 ("net/mlx5e: Rx, Split rep rx mpwqe handler from nic") > Fixes: f97d5c2a453e ("net/mlx5e: Add handle SHAMPO cqe support") > Fixes: 461017cb006a ("net/mlx5e: Support RX multi-packet WQE (Striding RQ)") > Signed-off-by: Leon Huang Fu > Signed-off-by: Leon Hwang > --- > drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h | 5 +++++ > drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 6 +++--- > 2 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h b/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h > index 7e191e1569e8..df8e671d5115 100644 > --- a/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h > +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h > @@ -583,4 +583,9 @@ static inline struct mlx5e_mpw_info *mlx5e_get_mpw_info(struct mlx5e_rq *rq, int > > return (struct mlx5e_mpw_info *)((char *)rq->mpwqe.info + array_size(i, isz)); > } > + > +static inline u16 mlx5e_rq_cqe_wqe_id(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe) > +{ > + return be16_to_cpu(cqe->wqe_id) & rq->mpwqe.wq.fbc.sz_m1; > +} > #endif > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c > index 1f6930c77437..25c04684271c 100644 > --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c > +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c > @@ -1957,7 +1957,7 @@ static void mlx5e_handle_rx_cqe_rep(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe) > static void mlx5e_handle_rx_cqe_mpwrq_rep(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe) > { > u16 cstrides = mpwrq_get_cqe_consumed_strides(cqe); > - u16 wqe_id = be16_to_cpu(cqe->wqe_id); > + u16 wqe_id = mlx5e_rq_cqe_wqe_id(rq, cqe); > struct mlx5e_mpw_info *wi = mlx5e_get_mpw_info(rq, wqe_id); > u16 stride_ix = mpwrq_get_cqe_stride_index(cqe); > u32 wqe_offset = stride_ix << rq->mpwqe.log_stride_sz; > @@ -2373,7 +2373,7 @@ static void mlx5e_handle_rx_cqe_mpwrq_shampo(struct mlx5e_rq *rq, struct mlx5_cq > u16 cstrides = mpwrq_get_cqe_consumed_strides(cqe); > u32 data_offset = wqe_offset & (PAGE_SIZE - 1); > u32 cqe_bcnt = mpwrq_get_cqe_byte_cnt(cqe); > - u16 wqe_id = be16_to_cpu(cqe->wqe_id); > + u16 wqe_id = mlx5e_rq_cqe_wqe_id(rq, cqe); > u32 page_idx = wqe_offset >> PAGE_SHIFT; > u16 head_size = cqe->shampo.header_size; > struct sk_buff **skb = &rq->hw_gro_data->skb; > @@ -2478,7 +2478,7 @@ static void mlx5e_handle_rx_cqe_mpwrq_shampo(struct mlx5e_rq *rq, struct mlx5_cq > static void mlx5e_handle_rx_cqe_mpwrq(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe) > { > u16 cstrides = mpwrq_get_cqe_consumed_strides(cqe); > - u16 wqe_id = be16_to_cpu(cqe->wqe_id); > + u16 wqe_id = mlx5e_rq_cqe_wqe_id(rq, cqe); > struct mlx5e_mpw_info *wi = mlx5e_get_mpw_info(rq, wqe_id); > u16 stride_ix = mpwrq_get_cqe_stride_index(cqe); > u32 wqe_offset = stride_ix << rq->mpwqe.log_stride_sz;