From: Arun Ramadoss <arun.ramadoss@xxxxxxxxxxxxx> commit 36c0d935015766bf20d621c18313f17691bda5e3 upstream. In the ksz9477_fdb_dump function it reads the ALU control register and exit from the timeout loop if there is valid entry or search is complete. After exiting the loop, it reads the alu entry and report to the user space irrespective of entry is valid. It works till the valid entry. If the loop exited when search is complete, it reads the alu table. The table returns all ones and it is reported to user space. So bridge fdb show gives ff:ff:ff:ff:ff:ff as last entry for every port. To fix it, after exiting the loop the entry is reported only if it is valid one. Fixes: b987e98e50ab ("dsa: add DSA switch driver for Microchip KSZ9477") Signed-off-by: Arun Ramadoss <arun.ramadoss@xxxxxxxxxxxxx> Reviewed-by: Vladimir Oltean <olteanv@xxxxxxxxx> Link: https://lore.kernel.org/r/20220816105516.18350-1-arun.ramadoss@xxxxxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/dsa/microchip/ksz9477.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/net/dsa/microchip/ksz9477.c +++ b/drivers/net/dsa/microchip/ksz9477.c @@ -766,6 +766,9 @@ static int ksz9477_port_fdb_dump(struct goto exit; } + if (!(ksz_data & ALU_VALID)) + continue; + /* read ALU table */ ksz9477_read_table(dev, alu_table);