net: dsa: mxl862xx: disable the stats poll on teardown

mxl862xx_setup() arms the stats poll before mxl862xx_setup_mdio(), and
nothing stops it until dsa_register_switch() has returned an error to
mxl862xx_probe(). DSA frees the dsa_port list before it returns, so a
poll that fires once .setup or a later step of dsa_tree_setup() has
failed walks freed ports. On shutdown the user ports stay registered,
and the WORK_STOPPED flag test in mxl862xx_get_stats64() is not atomic
with the cancel in mxl862xx_shutdown(), so a re-arm that read the flag
before it was set queues the poll after cancel_delayed_work_sync() has
returned.

Arm the poll once .setup has succeeded and stop it from a .teardown op,
which DSA calls on unregister and after a failed registration, in both
cases before it frees the ports. Use disable_delayed_work_sync() there
and in shutdown(): it drains a running poll as the cancel did and turns
every later attempt to queue the work into a no-op, so the re-arm
cannot bring the poll back. remove() and the probe error path only set
WORK_STOPPED, which crc_err_work tests before it walks the ports.

Fixes: a21d33a5265f ("net: dsa: mxl862xx: implement .get_stats64")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://patch.msgid.link/1eb6f7fc1789b67e4b11e3f4d5ff080d0b6f7cbb.1789045590.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions