Hi all,

After merging the net-next tree, today's linux-next build (x86_64
allmodconfig) failed like this:

In file included from include/linux/string.h:253,
                 from include/linux/bitmap.h:11,
                 from include/linux/cpumask.h:12,
                 from arch/x86/include/asm/cpumask.h:5,
                 from arch/x86/include/asm/msr.h:11,
                 from arch/x86/include/asm/processor.h:22,
                 from arch/x86/include/asm/timex.h:5,
                 from include/linux/timex.h:65,
                 from include/linux/time32.h:13,
                 from include/linux/time.h:60,
                 from include/linux/ktime.h:24,
                 from include/linux/timer.h:6,
                 from include/linux/netdevice.h:24,
                 from include/trace/events/xdp.h:8,
                 from include/linux/bpf_trace.h:5,
                 from drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c:33:
In function 'fortify_memset_chk',
    inlined from 'mlx5e_xmit_xdp_frame' at drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c:438:3:
include/linux/fortify-string.h:242:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
  242 |                         __write_overflow_field(p_size_field, size);
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Caused by commit

  9ded70fa1d81 ("net/mlx5e: Don't prefill WQEs in XDP SQ in the multi buffer mode")

exposed by the kspp tree.

I have applied the following fix patch for today (a better one is
probably possible).

From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Mon, 21 Mar 2022 18:29:24 +1100
Subject: [PATCH] fxup for "net/mlx5e: Don't prefill WQEs in XDP SQ in the multi buffer mode"

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---
 drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 3 +--
 include/linux/mlx5/qp.h                          | 5 +++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
index f35b62ce4c07..8f321a6c0809 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
@@ -435,8 +435,7 @@ mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptxd,
 		u8 num_pkts = 1 + num_frags;
 		int i;
 
-		memset(&cseg->signature, 0, sizeof(*cseg) -
-		       sizeof(cseg->opmod_idx_opcode) - sizeof(cseg->qpn_ds));
+		memset(&cseg->trailer, 0, sizeof(cseg->trailer));
 		memset(eseg, 0, sizeof(*eseg) - sizeof(eseg->trailer));
 
 		eseg->inline_hdr.sz = cpu_to_be16(inline_hdr_sz);
diff --git a/include/linux/mlx5/qp.h b/include/linux/mlx5/qp.h
index 61e48d459b23..8bda3ba5b109 100644
--- a/include/linux/mlx5/qp.h
+++ b/include/linux/mlx5/qp.h
@@ -202,6 +202,9 @@ struct mlx5_wqe_fmr_seg {
 struct mlx5_wqe_ctrl_seg {
 	__be32			opmod_idx_opcode;
 	__be32			qpn_ds;
+
+	struct_group(trailer,
+
 	u8			signature;
 	u8			rsvd[2];
 	u8			fm_ce_se;
@@ -211,6 +214,8 @@ struct mlx5_wqe_ctrl_seg {
 		__be32		umr_mkey;
 		__be32		tis_tir_num;
 	};
+
+	); /* end of trailer group */
 };
 
 #define MLX5_WQE_CTRL_DS_MASK 0x3f
-- 
2.34.1

-- 
Cheers,
Stephen Rothwell