bnxt_en: Fix uninitialized variable usage in bnxt_rx_pkt(). [Linux 5.1]

bnxt_en: Fix uninitialized variable usage in bnxt_rx_pkt(). [Linux 5.1]

This Linux kernel change "bnxt_en: Fix uninitialized variable usage in bnxt_rx_pkt()" is included in the Linux 5.1 release. This change is authored by Michael Chan <michael.chan [at] broadcom.com> on Thu Apr 25 22:31:55 2019 -0400. The commit for this change in Linux stable tree is 0b397b1 (patch).

bnxt_en: Fix uninitialized variable usage in bnxt_rx_pkt().

In bnxt_rx_pkt(), if the driver encounters BD errors, it will recycle
the buffers and jump to the end where the uninitailized variable "len"
is referenced.  Fix it by adding a new jump label that will skip
the length update.  This is the most correct fix since the length
may not be valid when we get this type of error.

Fixes: 6a8788f25625 ("bnxt_en: add support for software dynamic interrupt moderation")
Reported-by: Nathan Chancellor <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Signed-off-by: Michael Chan <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
Tested-by: Nathan Chancellor <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

There are 9 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index b6cb7b8..52ade13 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -1625,7 +1625,7 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
            netdev_warn(bp->dev, "RX buffer error %x\n", rx_err);
            bnxt_sched_reset(bp, rxr);
        }
-       goto next_rx;
+       goto next_rx_no_len;
    }

    len = le32_to_cpu(rxcmp->rx_cmp_len_flags_type) >> RX_CMP_LEN_SHIFT;
@@ -1706,12 +1706,13 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
    rc = 1;

 next_rx:
-   rxr->rx_prod = NEXT_RX(prod);
-   rxr->rx_next_cons = NEXT_RX(cons);
-
    cpr->rx_packets += 1;
    cpr->rx_bytes += len;

+next_rx_no_len:
+   rxr->rx_prod = NEXT_RX(prod);
+   rxr->rx_next_cons = NEXT_RX(cons);
+
 next_rx_no_prod_no_len:
    *raw_cons = tmp_raw_cons;

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